21562540 has 12 divisors (see below), whose sum is σ = 45281376. Its totient is φ = 8625008.

The previous prime is 21562507. The next prime is 21562559. The reversal of 21562540 is 4526512.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 539044 + ... + 539083.

It is an arithmetic number, because the mean of its divisors is an integer number (3773448).

Almost surely, 2^21562540 is an apocalyptic number.

21562540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21562540 is an abundant number, since it is smaller than the sum of its proper divisors (23718836).

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

21562540 is a wasteful number, since it uses less digits than its factorization.

21562540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078136 (or 1078134 counting only the distinct ones).

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

The square root of 21562540 is about 4643.5482123049. The cubic root of 21562540 is about 278.3342424901.

The spelling of 21562540 in words is "twenty-one million, five hundred sixty-two thousand, five hundred forty".