641878731 has 36 divisors (see below), whose sum is σ = 1007439888. Its totient is φ = 393636672.

The previous prime is 641878723. The next prime is 641878747. The reversal of 641878731 is 137878146.

It is not a de Polignac number, because 641878731 - 2³ = 641878723 is a prime.

It is a super-2 number, since 2×641878731² = 824016610620340722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (641878711) 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 35 ways as a sum of consecutive naturals, for example, 603306 + ... + 604368.

Almost surely, 2^641878731 is an apocalyptic number.

641878731 is a deficient number, since it is larger than the sum of its proper divisors (365561157).

641878731 is a wasteful number, since it uses less digits than its factorization.

641878731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1492 (or 1476 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 641878731 is about 25335.3257527903. The cubic root of 641878731 is about 862.6163029051.

The spelling of 641878731 in words is "six hundred forty-one million, eight hundred seventy-eight thousand, seven hundred thirty-one".