640749529 has 6 divisors (see below), whose sum is σ = 745361754. Its totient is φ = 549213840.

The previous prime is 640749523. The next prime is 640749569. The reversal of 640749529 is 925947046.

640749529 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 446899600 + 193849929 = 21140^2 + 13923^2 .

It is not a de Polignac number, because 640749529 - 2¹⁵ = 640716761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640749523) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6538212 + ... + 6538309.

It is an arithmetic number, because the mean of its divisors is an integer number (124226959).

Almost surely, 2^640749529 is an apocalyptic number.

It is an amenable number.

640749529 is a deficient number, since it is larger than the sum of its proper divisors (104612225).

640749529 is a wasteful number, since it uses less digits than its factorization.

640749529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13076535 (or 13076528 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 46.

The square root of 640749529 is about 25313.0308141874. The cubic root of 640749529 is about 862.1101637834.

It can be divided in two parts, 640749 and 529, that added together give a triangular number (641278 = T₁₁₃₂).

The spelling of 640749529 in words is "six hundred forty million, seven hundred forty-nine thousand, five hundred twenty-nine".