646738157 has 12 divisors (see below), whose sum is σ = 741512340. Its totient is φ = 561869568.

The previous prime is 646738129. The next prime is 646738177. The reversal of 646738157 is 751837646.

646738157 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 163353961 + 483384196 = 12781^2 + 21986^2 .

It is not a de Polignac number, because 646738157 - 2¹⁴ = 646721773 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 (646738177) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 109682 + ... + 115427.

It is an arithmetic number, because the mean of its divisors is an integer number (61792695).

Almost surely, 2^646738157 is an apocalyptic number.

It is an amenable number.

646738157 is a deficient number, since it is larger than the sum of its proper divisors (94774183).

646738157 is a wasteful number, since it uses less digits than its factorization.

646738157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225152 (or 225139 counting only the distinct ones).

The product of its digits is 846720, while the sum is 47.

The square root of 646738157 is about 25431.0471078169. The cubic root of 646738157 is about 864.7876819716.

The spelling of 646738157 in words is "six hundred forty-six million, seven hundred thirty-eight thousand, one hundred fifty-seven".