21075907 has 2 divisors, whose sum is σ = 21075908. Its totient is φ = 21075906.

The previous prime is 21075871. The next prime is 21075917. The reversal of 21075907 is 70957012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21075907 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21075917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10537953 + 10537954.

It is an arithmetic number, because the mean of its divisors is an integer number (10537954).

Almost surely, 2^21075907 is an apocalyptic number.

21075907 is a deficient number, since it is larger than the sum of its proper divisors (1).

21075907 is an equidigital number, since it uses as much as digits as its factorization.

21075907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 21075907 is about 4590.8503569600. The cubic root of 21075907 is about 276.2244332515.

The spelling of 21075907 in words is "twenty-one million, seventy-five thousand, nine hundred seven".