21373207 has 2 divisors, whose sum is σ = 21373208. Its totient is φ = 21373206.

The previous prime is 21373171. The next prime is 21373223. The reversal of 21373207 is 70237312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21373207 - 2²³ = 12984599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21373237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686603 + 10686604.

It is an arithmetic number, because the mean of its divisors is an integer number (10686604).

Almost surely, 2^21373207 is an apocalyptic number.

21373207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21373207 is an equidigital number, since it uses as much as digits as its factorization.

21373207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1764, while the sum is 25.

The square root of 21373207 is about 4623.1165894881. The cubic root of 21373207 is about 277.5171950495.

The spelling of 21373207 in words is "twenty-one million, three hundred seventy-three thousand, two hundred seven".