646738125 has 40 divisors (see below), whose sum is σ = 1175548704. Its totient is φ = 313560000.

The previous prime is 646738121. The next prime is 646738129. The reversal of 646738125 is 521837646.

It is an interprime number because it is at equal distance from previous prime (646738121) and next prime (646738129).

It is not a de Polignac number, because 646738125 - 2² = 646738121 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646738121) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 4947 + ... + 36303.

Almost surely, 2^646738125 is an apocalyptic number.

It is an amenable number.

646738125 is a deficient number, since it is larger than the sum of its proper divisors (528810579).

646738125 is a wasteful number, since it uses less digits than its factorization.

646738125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31391 (or 31376 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 646738125 is about 25431.0464786646. The cubic root of 646738125 is about 864.7876677087.

It can be divided in two parts, 6467381 and 25, that added together give a triangular number (6467406 = T₃₅₉₆).

The spelling of 646738125 in words is "six hundred forty-six million, seven hundred thirty-eight thousand, one hundred twenty-five".