21156607 has 2 divisors, whose sum is σ = 21156608. Its totient is φ = 21156606.

The previous prime is 21156599. The next prime is 21156613. The reversal of 21156607 is 70665112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21156607 - 2³ = 21156599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21156647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578303 + 10578304.

It is an arithmetic number, because the mean of its divisors is an integer number (10578304).

Almost surely, 2^21156607 is an apocalyptic number.

21156607 is a deficient number, since it is larger than the sum of its proper divisors (1).

21156607 is an equidigital number, since it uses as much as digits as its factorization.

21156607 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21156607 is about 4599.6311808666. The cubic root of 21156607 is about 276.5765402152.

The spelling of 21156607 in words is "twenty-one million, one hundred fifty-six thousand, six hundred seven".