21152297 has 4 divisors (see below), whose sum is σ = 21162756. Its totient is φ = 21141840.

The previous prime is 21152291. The next prime is 21152309. The reversal of 21152297 is 79225112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8271376 + 12880921 = 2876^2 + 3589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21152297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21152291) 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, 1118 + ... + 6599.

It is an arithmetic number, because the mean of its divisors is an integer number (5290689).

Almost surely, 2^21152297 is an apocalyptic number.

It is an amenable number.

21152297 is a deficient number, since it is larger than the sum of its proper divisors (10459).

21152297 is an equidigital number, since it uses as much as digits as its factorization.

21152297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10458.

The product of its digits is 2520, while the sum is 29.

The square root of 21152297 is about 4599.1626411772. The cubic root of 21152297 is about 276.5577576533.

The spelling of 21152297 in words is "twenty-one million, one hundred fifty-two thousand, two hundred ninety-seven".