21930637 has 4 divisors (see below), whose sum is σ = 22208320. Its totient is φ = 21652956.

The previous prime is 21930619. The next prime is 21930647. The reversal of 21930637 is 73603912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21930637 - 2²³ = 13542029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21930599 and 21930608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21930647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138723 + ... + 138880.

It is an arithmetic number, because the mean of its divisors is an integer number (5552080).

Almost surely, 2^21930637 is an apocalyptic number.

It is an amenable number.

21930637 is a deficient number, since it is larger than the sum of its proper divisors (277683).

21930637 is an equidigital number, since it uses as much as digits as its factorization.

21930637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277682.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 21930637 is about 4683.0158018098. The cubic root of 21930637 is about 279.9091414384.

The spelling of 21930637 in words is "twenty-one million, nine hundred thirty thousand, six hundred thirty-seven".