21315697 has 8 divisors (see below), whose sum is σ = 23345280. Its totient is φ = 19341840.

The previous prime is 21315689. The next prime is 21315709. The reversal of 21315697 is 79651312.

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 21315697 - 2³ = 21315689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21315607) 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, 13129 + ... + 14662.

It is an arithmetic number, because the mean of its divisors is an integer number (2918160).

Almost surely, 2^21315697 is an apocalyptic number.

It is an amenable number.

21315697 is a deficient number, since it is larger than the sum of its proper divisors (2029583).

21315697 is a wasteful number, since it uses less digits than its factorization.

21315697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27863.

The product of its digits is 11340, while the sum is 34.

The square root of 21315697 is about 4616.8925696836. The cubic root of 21315697 is about 277.2680614787.

The spelling of 21315697 in words is "twenty-one million, three hundred fifteen thousand, six hundred ninety-seven".