21675207 has 4 divisors (see below), whose sum is σ = 28900280. Its totient is φ = 14450136.

The previous prime is 21675197. The next prime is 21675211. The reversal of 21675207 is 70257612.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21675207 - 2¹⁰ = 21674183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21675287) 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, 3612532 + ... + 3612537.

It is an arithmetic number, because the mean of its divisors is an integer number (7225070).

Almost surely, 2^21675207 is an apocalyptic number.

21675207 is a deficient number, since it is larger than the sum of its proper divisors (7225073).

21675207 is an equidigital number, since it uses as much as digits as its factorization.

21675207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7225072.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 21675207 is about 4655.6639698329. The cubic root of 21675207 is about 278.8181778042.

The spelling of 21675207 in words is "twenty-one million, six hundred seventy-five thousand, two hundred seven".