640147956 has 36 divisors (see below), whose sum is σ = 1737546048. Its totient is φ = 182899248.

The previous prime is 640147951. The next prime is 640147957. The reversal of 640147956 is 659741046.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640147951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 543756 + ... + 544931.

It is an arithmetic number, because the mean of its divisors is an integer number (48265168).

Almost surely, 2^640147956 is an apocalyptic number.

It is an amenable number.

640147956 is an abundant number, since it is smaller than the sum of its proper divisors (1097398092).

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

640147956 is a wasteful number, since it uses less digits than its factorization.

640147956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1088708 (or 1088699 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 42.

The square root of 640147956 is about 25301.1453495687. The cubic root of 640147956 is about 861.8402795499.

The spelling of 640147956 in words is "six hundred forty million, one hundred forty-seven thousand, nine hundred fifty-six".