21607313 has 16 divisors (see below), whose sum is σ = 27995520. Its totient is φ = 16194816.

The previous prime is 21607309. The next prime is 21607319. The reversal of 21607313 is 31370612.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21607313 - 2² = 21607309 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21607319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4520 + ... + 7977.

It is an arithmetic number, because the mean of its divisors is an integer number (1749720).

Almost surely, 2^21607313 is an apocalyptic number.

It is an amenable number.

21607313 is a deficient number, since it is larger than the sum of its proper divisors (6388207).

21607313 is a wasteful number, since it uses less digits than its factorization.

21607313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12536.

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 21607313 is about 4648.3667024020. The cubic root of 21607313 is about 278.5267560437.

Adding to 21607313 its reverse (31370612), we get a palindrome (52977925).

The spelling of 21607313 in words is "twenty-one million, six hundred seven thousand, three hundred thirteen".