21397153 has 16 divisors (see below), whose sum is σ = 23069952. Its totient is φ = 19800000.

The previous prime is 21397139. The next prime is 21397171. The reversal of 21397153 is 35179312.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21397153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21397253) 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 15 ways as a sum of consecutive naturals, for example, 141628 + ... + 141778.

It is an arithmetic number, because the mean of its divisors is an integer number (1441872).

Almost surely, 2^21397153 is an apocalyptic number.

21397153 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21397153 is a deficient number, since it is larger than the sum of its proper divisors (1672799).

21397153 is a wasteful number, since it uses less digits than its factorization.

21397153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336.

The product of its digits is 5670, while the sum is 31.

The square root of 21397153 is about 4625.7056758942. The cubic root of 21397153 is about 277.6207974477.

The spelling of 21397153 in words is "twenty-one million, three hundred ninety-seven thousand, one hundred fifty-three".