21907201 has 4 divisors (see below), whose sum is σ = 22859712. Its totient is φ = 20954692.

The previous prime is 21907189. The next prime is 21907229. The reversal of 21907201 is 10270912.

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 21907201 - 2¹⁹ = 21382913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21907901) 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, 476221 + ... + 476266.

It is an arithmetic number, because the mean of its divisors is an integer number (5714928).

Almost surely, 2^21907201 is an apocalyptic number.

It is an amenable number.

21907201 is a deficient number, since it is larger than the sum of its proper divisors (952511).

21907201 is an equidigital number, since it uses as much as digits as its factorization.

21907201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 952510.

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 21907201 is about 4680.5128992451. The cubic root of 21907201 is about 279.8093983443.

The spelling of 21907201 in words is "twenty-one million, nine hundred seven thousand, two hundred one".