21912201 has 20 divisors (see below), whose sum is σ = 34660692. Its totient is φ = 13747968.

The previous prime is 21912193. The next prime is 21912211. The reversal of 21912201 is 10221912.

It can be written as a sum of positive squares in 2 ways, for example, as 17438976 + 4473225 = 4176^2 + 2115^2 .

It is not a de Polignac number, because 21912201 - 2³ = 21912193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21912211) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6580 + ... + 9333.

Almost surely, 2^21912201 is an apocalyptic number.

It is an amenable number.

21912201 is a deficient number, since it is larger than the sum of its proper divisors (12748491).

21912201 is a wasteful number, since it uses less digits than its factorization.

21912201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15942 (or 15933 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21912201 is about 4681.0469982687. The cubic root of 21912201 is about 279.8306842001.

The spelling of 21912201 in words is "twenty-one million, nine hundred twelve thousand, two hundred one".