640157760 has 336 divisors, whose sum is σ = 2436400512. Its totient is φ = 154260480.

The previous prime is 640157759. The next prime is 640157767. The reversal of 640157760 is 67751046.

640157760 is a `hidden beast` number, since 640 + 1 + 5 + 7 + 7 + 6 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (640157767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3833197 + ... + 3833363.

It is an arithmetic number, because the mean of its divisors is an integer number (7251192).

Almost surely, 2^640157760 is an apocalyptic number.

640157760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640157760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1218200256).

640157760 is an abundant number, since it is smaller than the sum of its proper divisors (1796242752).

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

640157760 is a wasteful number, since it uses less digits than its factorization.

640157760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 640157760 is about 25301.3390949965. The cubic root of 640157760 is about 861.8446792822.

The spelling of 640157760 in words is "six hundred forty million, one hundred fifty-seven thousand, seven hundred sixty".