23021520 has 40 divisors (see below), whose sum is σ = 71367456. Its totient is φ = 6139008.

The previous prime is 23021513. The next prime is 23021533. The reversal of 23021520 is 2512032.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×23021520² = 1059980766220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a zygodrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 23021520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47722 + ... + 48201.

Almost surely, 2^23021520 is an apocalyptic number.

23021520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

23021520 is an abundant number, since it is smaller than the sum of its proper divisors (48345936).

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

23021520 is a wasteful number, since it uses less digits than its factorization.

23021520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95939 (or 95933 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 23021520 is about 4798.0746138425. The cubic root of 23021520 is about 284.4753660142.

Subtracting from 23021520 its sum of digits (15), we obtain a triangular number (23021505 = T₆₇₈₅).

Adding to 23021520 its reverse (2512032), we get a palindrome (25533552).

The spelling of 23021520 in words is "twenty-three million, twenty-one thousand, five hundred twenty".