640623144 has 32 divisors (see below), whose sum is σ = 1830352320. Its totient is φ = 183035136.

The previous prime is 640623127. The next prime is 640623161. The reversal of 640623144 is 441326046.

640623144 = T₁₁₉₂₇ + T₁₁₉₂₈ + ... + T₁₁₉₃₅.

It is an interprime number because it is at equal distance from previous prime (640623127) and next prime (640623161).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1906449 + ... + 1906784.

It is an arithmetic number, because the mean of its divisors is an integer number (57198510).

Almost surely, 2^640623144 is an apocalyptic number.

It is an amenable number.

640623144 is an abundant number, since it is smaller than the sum of its proper divisors (1189729176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640623144 is a wasteful number, since it uses less digits than its factorization.

640623144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3813249 (or 3813245 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 640623144 is about 25310.5342495966. The cubic root of 640623144 is about 862.0534775887.

The spelling of 640623144 in words is "six hundred forty million, six hundred twenty-three thousand, one hundred forty-four".