646974157 has 2 divisors, whose sum is σ = 646974158. Its totient is φ = 646974156.

The previous prime is 646974101. The next prime is 646974161. The reversal of 646974157 is 751479646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 370716516 + 276257641 = 19254^2 + 16621^2 .

It is a cyclic number.

It is not a de Polignac number, because 646974157 - 2¹⁵ = 646941389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 646974157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646944157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323487078 + 323487079.

It is an arithmetic number, because the mean of its divisors is an integer number (323487079).

Almost surely, 2^646974157 is an apocalyptic number.

It is an amenable number.

646974157 is a deficient number, since it is larger than the sum of its proper divisors (1).

646974157 is an equidigital number, since it uses as much as digits as its factorization.

646974157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 49.

The square root of 646974157 is about 25435.6866822974. The cubic root of 646974157 is about 864.8928585263.

The spelling of 646974157 in words is "six hundred forty-six million, nine hundred seventy-four thousand, one hundred fifty-seven".