21310697 has 8 divisors (see below), whose sum is σ = 21631752. Its totient is φ = 20992000.

The previous prime is 21310669. The next prime is 21310739. The reversal of 21310697 is 79601312.

It can be written as a sum of positive squares in 4 ways, for example, as 13039321 + 8271376 = 3611^2 + 2876^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21310697 - 2¹⁸ = 21048553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21310607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25547 + ... + 26367.

It is an arithmetic number, because the mean of its divisors is an integer number (2703969).

Almost surely, 2^21310697 is an apocalyptic number.

It is an amenable number.

21310697 is a deficient number, since it is larger than the sum of its proper divisors (321055).

21310697 is a wasteful number, since it uses less digits than its factorization.

21310697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1179.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 21310697 is about 4616.3510481765. The cubic root of 21310697 is about 277.2463802936.

The spelling of 21310697 in words is "twenty-one million, three hundred ten thousand, six hundred ninety-seven".