21397562 has 8 divisors (see below), whose sum is σ = 32130516. Its totient is φ = 10687392.

The previous prime is 21397559. The next prime is 21397573. The reversal of 21397562 is 26579312.

It can be written as a sum of positive squares in 2 ways, for example, as 19545241 + 1852321 = 4421^2 + 1361^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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, 3113 + ... + 7244.

Almost surely, 2^21397562 is an apocalyptic number.

21397562 is a deficient number, since it is larger than the sum of its proper divisors (10732954).

21397562 is a wasteful number, since it uses less digits than its factorization.

21397562 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11392.

The product of its digits is 22680, while the sum is 35.

The square root of 21397562 is about 4625.7498851538. The cubic root of 21397562 is about 277.6225663152.

The spelling of 21397562 in words is "twenty-one million, three hundred ninety-seven thousand, five hundred sixty-two".