20785440 has 96 divisors (see below), whose sum is σ = 70531776. Its totient is φ = 5114880.

The previous prime is 20785439. The next prime is 20785447. The reversal of 20785440 is 4458702.

20785440 = T₇₆₇ + T₇₆₈ + ... + T₈₃₁.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20785398 and 20785407.

It is not an unprimeable number, because it can be changed into a prime (20785447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4575 + ... + 7905.

It is an arithmetic number, because the mean of its divisors is an integer number (734706).

Almost surely, 2^20785440 is an apocalyptic number.

20785440 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 20785440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35265888).

20785440 is an abundant number, since it is smaller than the sum of its proper divisors (49746336).

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

20785440 is a wasteful number, since it uses less digits than its factorization.

20785440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3362 (or 3354 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 30.

The square root of 20785440 is about 4559.1051753606. The cubic root of 20785440 is about 274.9495885556.

The spelling of 20785440 in words is "twenty million, seven hundred eighty-five thousand, four hundred forty".