20307840 has 128 divisors (see below), whose sum is σ = 74027520. Its totient is φ = 4638720.

The previous prime is 20307817. The next prime is 20307863. The reversal of 20307840 is 4870302.

It is an interprime number because it is at equal distance from previous prime (20307817) and next prime (20307863).

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20307840.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12685 + ... + 14195.

It is an arithmetic number, because the mean of its divisors is an integer number (578340).

Almost surely, 2^20307840 is an apocalyptic number.

20307840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20307840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37013760).

20307840 is an abundant number, since it is smaller than the sum of its proper divisors (53719680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20307840 is a wasteful number, since it uses less digits than its factorization.

20307840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540 (or 1528 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 20307840 is about 4506.4220840929. The cubic root of 20307840 is about 272.8273539763.

It can be divided in two parts, 2030 and 7840, that added together give a triangular number (9870 = T₁₄₀).

The spelling of 20307840 in words is "twenty million, three hundred seven thousand, eight hundred forty".