640985229 has 12 divisors (see below), whose sum is σ = 966122976. Its totient is φ = 408744072.

The previous prime is 640985203. The next prime is 640985237. The reversal of 640985229 is 922589046.

It is not a de Polignac number, because 640985229 - 2¹³ = 640977037 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640985239) 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 11 ways as a sum of consecutive naturals, for example, 1548067 + ... + 1548480.

It is an arithmetic number, because the mean of its divisors is an integer number (80510248).

Almost surely, 2^640985229 is an apocalyptic number.

640985229 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

640985229 is a deficient number, since it is larger than the sum of its proper divisors (325137747).

640985229 is a wasteful number, since it uses less digits than its factorization.

640985229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3096576 (or 3096573 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 640985229 is about 25317.6860909523. The cubic root of 640985229 is about 862.2158600271.

The spelling of 640985229 in words is "six hundred forty million, nine hundred eighty-five thousand, two hundred twenty-nine".