640136983 has 4 divisors (see below), whose sum is σ = 640199728. Its totient is φ = 640074240.

The previous prime is 640136971. The next prime is 640137019. The reversal of 640136983 is 389631046.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640136983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640136933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12138 + ... + 37783.

It is an arithmetic number, because the mean of its divisors is an integer number (160049932).

Almost surely, 2^640136983 is an apocalyptic number.

640136983 is a deficient number, since it is larger than the sum of its proper divisors (62745).

640136983 is a wasteful number, since it uses less digits than its factorization.

640136983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62744.

The product of its (nonzero) digits is 93312, while the sum is 40.

The square root of 640136983 is about 25300.9285007487. The cubic root of 640136983 is about 861.8353551532.

The spelling of 640136983 in words is "six hundred forty million, one hundred thirty-six thousand, nine hundred eighty-three".