647640642 has 32 divisors (see below), whose sum is σ = 1424729664. Its totient is φ = 196252320.

The previous prime is 647640611. The next prime is 647640649. The reversal of 647640642 is 246046746.

It is a self number, because there is not a number n which added to its sum of digits gives 647640642.

It is not an unprimeable number, because it can be changed into a prime (647640649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32563 + ... + 48534.

It is an arithmetic number, because the mean of its divisors is an integer number (44522802).

Almost surely, 2^647640642 is an apocalyptic number.

647640642 is an abundant number, since it is smaller than the sum of its proper divisors (777089022).

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

647640642 is a wasteful number, since it uses less digits than its factorization.

647640642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81135 (or 81113 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 39.

The square root of 647640642 is about 25448.7846861103. The cubic root of 647640642 is about 865.1897484320.

The spelling of 647640642 in words is "six hundred forty-seven million, six hundred forty thousand, six hundred forty-two".