640155281764 has 12 divisors (see below), whose sum is σ = 1120470166144. Its totient is φ = 320020948584.

The previous prime is 640155281761. The next prime is 640155281791. The reversal of 640155281764 is 467182551046.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (640155281761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14147664 + ... + 14192839.

Almost surely, 2^640155281764 is an apocalyptic number.

It is an amenable number.

640155281764 is a deficient number, since it is larger than the sum of its proper divisors (480314884380).

640155281764 is a wasteful number, since it uses less digits than its factorization.

640155281764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28346154 (or 28346152 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 49.

The spelling of 640155281764 in words is "six hundred forty billion, one hundred fifty-five million, two hundred eighty-one thousand, seven hundred sixty-four".