21372722 has 18 divisors (see below), whose sum is σ = 37373247. Its totient is φ = 9140124.

The previous prime is 21372719. The next prime is 21372737. The reversal of 21372722 is 22727312.

It can be written as a sum of positive squares in only one way, i.e., 10686361 + 10686361 = 3269^2 + 3269^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3269.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21372691 and 21372700.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 45533 + ... + 45999.

Almost surely, 2^21372722 is an apocalyptic number.

21372722 is a deficient number, since it is larger than the sum of its proper divisors (16000525).

21372722 is an frugal number, since it uses more digits than its factorization.

21372722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950 (or 476 counting only the distinct ones).

The product of its digits is 2352, while the sum is 26.

The square root of 21372722 is about 4623.0641353976. The cubic root of 21372722 is about 277.5150958971.

The spelling of 21372722 in words is "twenty-one million, three hundred seventy-two thousand, seven hundred twenty-two".