20915740 has 48 divisors (see below), whose sum is σ = 46992960. Its totient is φ = 7800320.

The previous prime is 20915723. The next prime is 20915743. The reversal of 20915740 is 4751902.

It is a happy number.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20915699 and 20915708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20915743) by changing a digit.

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, 18306 + ... + 19414.

It is an arithmetic number, because the mean of its divisors is an integer number (979020).

Almost surely, 2^20915740 is an apocalyptic number.

20915740 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 20915740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23496480).

20915740 is an abundant number, since it is smaller than the sum of its proper divisors (26077220).

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

20915740 is a wasteful number, since it uses less digits than its factorization.

20915740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182 (or 1180 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 20915740 is about 4573.3729347168. The cubic root of 20915740 is about 275.5229278582.

The spelling of 20915740 in words is "twenty million, nine hundred fifteen thousand, seven hundred forty".