21423697 has 8 divisors (see below), whose sum is σ = 23279360. Its totient is φ = 19640880.

The previous prime is 21423679. The next prime is 21423709. The reversal of 21423697 is 79632412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21423497) 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, 17598 + ... + 18775.

It is an arithmetic number, because the mean of its divisors is an integer number (2909920).

Almost surely, 2^21423697 is an apocalyptic number.

It is an amenable number.

21423697 is a deficient number, since it is larger than the sum of its proper divisors (1855663).

21423697 is a wasteful number, since it uses less digits than its factorization.

21423697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36423.

The product of its digits is 18144, while the sum is 34.

The square root of 21423697 is about 4628.5739704579. The cubic root of 21423697 is about 277.7355498060.

The spelling of 21423697 in words is "twenty-one million, four hundred twenty-three thousand, six hundred ninety-seven".