646640254 has 32 divisors (see below), whose sum is σ = 1108126656. Its totient is φ = 280358400.

The previous prime is 646640221. The next prime is 646640257. The reversal of 646640254 is 452046646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646640257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308799 + ... + 310885.

It is an arithmetic number, because the mean of its divisors is an integer number (34628958).

Almost surely, 2^646640254 is an apocalyptic number.

646640254 is a deficient number, since it is larger than the sum of its proper divisors (461486402).

646640254 is a wasteful number, since it uses less digits than its factorization.

646640254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2820.

The product of its (nonzero) digits is 138240, while the sum is 37.

The square root of 646640254 is about 25429.1221633780. The cubic root of 646640254 is about 864.7440426821.

The spelling of 646640254 in words is "six hundred forty-six million, six hundred forty thousand, two hundred fifty-four".