21272597 has 4 divisors (see below), whose sum is σ = 21333900. Its totient is φ = 21211296.

The previous prime is 21272579. The next prime is 21272611. The reversal of 21272597 is 79527212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9480241 + 11792356 = 3079^2 + 3434^2 .

It is a cyclic number.

It is not a de Polignac number, because 21272597 - 2²² = 17078293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21272507) 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, 30128 + ... + 30825.

It is an arithmetic number, because the mean of its divisors is an integer number (5333475).

Almost surely, 2^21272597 is an apocalyptic number.

It is an amenable number.

21272597 is a deficient number, since it is larger than the sum of its proper divisors (61303).

21272597 is an equidigital number, since it uses as much as digits as its factorization.

21272597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61302.

The product of its digits is 17640, while the sum is 35.

The square root of 21272597 is about 4612.2225661822. Note that the first 3 decimals coincide. The cubic root of 21272597 is about 277.0810581807.

The spelling of 21272597 in words is "twenty-one million, two hundred seventy-two thousand, five hundred ninety-seven".