21357297 has 32 divisors (see below), whose sum is σ = 34594560. Its totient is φ = 12942720.

The previous prime is 21357263. The next prime is 21357299. The reversal of 21357297 is 79275312.

It is not a de Polignac number, because 21357297 - 2¹² = 21353201 is a prime.

It is a super-2 number, since 2×21357297² = 912268270292418, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21357299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24493 + ... + 25349.

It is an arithmetic number, because the mean of its divisors is an integer number (1081080).

Almost surely, 2^21357297 is an apocalyptic number.

21357297 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21357297 is a deficient number, since it is larger than the sum of its proper divisors (13237263).

21357297 is a wasteful number, since it uses less digits than its factorization.

21357297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950 (or 944 counting only the distinct ones).

The product of its digits is 26460, while the sum is 36.

The square root of 21357297 is about 4621.3955684403. The cubic root of 21357297 is about 277.4483176213.

The spelling of 21357297 in words is "twenty-one million, three hundred fifty-seven thousand, two hundred ninety-seven".