640156655340 has 36 divisors (see below), whose sum is σ = 1941808521744. Its totient is φ = 170708441376.

The previous prime is 640156655287. The next prime is 640156655371. The reversal of 640156655340 is 43556651046.

640156655340 is a `hidden beast` number, since 6 + 4 + 0 + 1 + 56 + 6 + 553 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1778212752 + ... + 1778213111.

It is an arithmetic number, because the mean of its divisors is an integer number (53939125604).

Almost surely, 2^640156655340 is an apocalyptic number.

640156655340 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640156655340 is an abundant number, since it is smaller than the sum of its proper divisors (1301651866404).

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

640156655340 is a wasteful number, since it uses less digits than its factorization.

640156655340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3556425878 (or 3556425873 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 640156655340 in words is "six hundred forty billion, one hundred fifty-six million, six hundred fifty-five thousand, three hundred forty".