21372929 has 8 divisors (see below), whose sum is σ = 22710240. Its totient is φ = 20056896.

The previous prime is 21372889. The next prime is 21372937. The reversal of 21372929 is 92927312.

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 21372929 - 2²⁴ = 4595713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21372229) 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, 3224 + ... + 7289.

It is an arithmetic number, because the mean of its divisors is an integer number (2838780).

It is a Proth number, since it is equal to 2609 ⋅ 2¹³ + 1 and 2609 < 2¹³.

Almost surely, 2^21372929 is an apocalyptic number.

It is an amenable number.

21372929 is a deficient number, since it is larger than the sum of its proper divisors (1337311).

21372929 is a wasteful number, since it uses less digits than its factorization.

21372929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10639.

The product of its digits is 13608, while the sum is 35.

The square root of 21372929 is about 4623.0865230926. The cubic root of 21372929 is about 277.5159918279.

The spelling of 21372929 in words is "twenty-one million, three hundred seventy-two thousand, nine hundred twenty-nine".