646403375 has 16 divisors (see below), whose sum is σ = 807493440. Its totient is φ = 516621600.

The previous prime is 646403327. The next prime is 646403377. The reversal of 646403375 is 573304646.

It is not a de Polignac number, because 646403375 - 2⁸ = 646403119 is a prime.

It is a super-2 number, since 2×646403375² = 835674646422781250, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646403377) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 179846 + ... + 183404.

It is an arithmetic number, because the mean of its divisors is an integer number (50468340).

Almost surely, 2^646403375 is an apocalyptic number.

646403375 is a deficient number, since it is larger than the sum of its proper divisors (161090065).

646403375 is a wasteful number, since it uses less digits than its factorization.

646403375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5027 (or 5017 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 38.

The square root of 646403375 is about 25424.4641044802. The cubic root of 646403375 is about 864.6384379968.

The spelling of 646403375 in words is "six hundred forty-six million, four hundred three thousand, three hundred seventy-five".