640376820 has 48 divisors (see below), whose sum is σ = 1992285120. Its totient is φ = 170767008.

The previous prime is 640376813. The next prime is 640376837. The reversal of 640376820 is 28673046.

640376820 is a `hidden beast` number, since 640 + 3 + 7 + 6 + 8 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 592402 + ... + 593481.

It is an arithmetic number, because the mean of its divisors is an integer number (41505940).

Almost surely, 2^640376820 is an apocalyptic number.

640376820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640376820 is an abundant number, since it is smaller than the sum of its proper divisors (1351908300).

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

640376820 is a wasteful number, since it uses less digits than its factorization.

640376820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1185901 (or 1185893 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 640376820 is about 25305.6677445982. The cubic root of 640376820 is about 861.9429749296.

The spelling of 640376820 in words is "six hundred forty million, three hundred seventy-six thousand, eight hundred twenty".