21397552 has 20 divisors (see below), whose sum is σ = 45227016. Its totient is φ = 9726080.

The previous prime is 21397517. The next prime is 21397559. The reversal of 21397552 is 25579312.

It is not an unprimeable number, because it can be changed into a prime (21397559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60613 + ... + 60964.

Almost surely, 2^21397552 is an apocalyptic number.

21397552 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21397552 is an abundant number, since it is smaller than the sum of its proper divisors (23829464).

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

21397552 is a wasteful number, since it uses less digits than its factorization.

21397552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121596 (or 121590 counting only the distinct ones).

The product of its digits is 18900, while the sum is 34.

The square root of 21397552 is about 4625.7488042478. The cubic root of 21397552 is about 277.6225230669.

The spelling of 21397552 in words is "twenty-one million, three hundred ninety-seven thousand, five hundred fifty-two".