21442597 has 4 divisors (see below), whose sum is σ = 23391936. Its totient is φ = 19493260.

The previous prime is 21442591. The next prime is 21442637. The reversal of 21442597 is 79524412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21442597 is a prime.

It is a super-2 number, since 2×21442597² = 919569932208818, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21442591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 974653 + ... + 974674.

It is an arithmetic number, because the mean of its divisors is an integer number (5847984).

Almost surely, 2^21442597 is an apocalyptic number.

It is an amenable number.

21442597 is a deficient number, since it is larger than the sum of its proper divisors (1949339).

21442597 is a wasteful number, since it uses less digits than its factorization.

21442597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949338.

The product of its digits is 20160, while the sum is 34.

The square root of 21442597 is about 4630.6151859121. The cubic root of 21442597 is about 277.8171986305.

The spelling of 21442597 in words is "twenty-one million, four hundred forty-two thousand, five hundred ninety-seven".