21652540 has 48 divisors (see below), whose sum is σ = 55968192. Its totient is φ = 6852096.

The previous prime is 21652537. The next prime is 21652639. The reversal of 21652540 is 4525612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4129 + ... + 7768.

It is an arithmetic number, because the mean of its divisors is an integer number (1166004).

Almost surely, 2^21652540 is an apocalyptic number.

21652540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21652540 is an abundant number, since it is smaller than the sum of its proper divisors (34315652).

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

21652540 is a wasteful number, since it uses less digits than its factorization.

21652540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11926 (or 11924 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 21652540 is about 4653.2289864136. The cubic root of 21652540 is about 278.7209518820.

The spelling of 21652540 in words is "twenty-one million, six hundred fifty-two thousand, five hundred forty".