640334751 has 32 divisors (see below), whose sum is σ = 1043980800. Its totient is φ = 340951680.

The previous prime is 640334749. The next prime is 640334753. The reversal of 640334751 is 157433046.

It is an interprime number because it is at equal distance from previous prime (640334749) and next prime (640334753).

It is not a de Polignac number, because 640334751 - 2¹ = 640334749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640334753) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11185 + ... + 37493.

It is an arithmetic number, because the mean of its divisors is an integer number (32624400).

Almost surely, 2^640334751 is an apocalyptic number.

640334751 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

640334751 is a deficient number, since it is larger than the sum of its proper divisors (403646049).

640334751 is a wasteful number, since it uses less digits than its factorization.

640334751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26399.

The product of its (nonzero) digits is 30240, while the sum is 33.

The square root of 640334751 is about 25304.8365139947. The cubic root of 640334751 is about 861.9240996508.

Adding to 640334751 its reverse (157433046), we get a palindrome (797767797).

The spelling of 640334751 in words is "six hundred forty million, three hundred thirty-four thousand, seven hundred fifty-one".