640372735 has 16 divisors (see below), whose sum is σ = 799506432. Its totient is φ = 491853600.

The previous prime is 640372687. The next prime is 640372769. The reversal of 640372735 is 537273046.

It is not a de Polignac number, because 640372735 - 2¹⁵ = 640339967 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640372694 and 640372703.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3420 + ... + 35950.

It is an arithmetic number, because the mean of its divisors is an integer number (49969152).

Almost surely, 2^640372735 is an apocalyptic number.

640372735 is a deficient number, since it is larger than the sum of its proper divisors (159133697).

640372735 is a wasteful number, since it uses less digits than its factorization.

640372735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32694.

The product of its (nonzero) digits is 105840, while the sum is 37.

The square root of 640372735 is about 25305.5870313257. The cubic root of 640372735 is about 861.9411421314.

The spelling of 640372735 in words is "six hundred forty million, three hundred seventy-two thousand, seven hundred thirty-five".