640036784 has 10 divisors (see below), whose sum is σ = 1240071300. Its totient is φ = 320018384.

The previous prime is 640036783. The next prime is 640036799. The reversal of 640036784 is 487630046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640036781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20001134 + ... + 20001165.

It is an arithmetic number, because the mean of its divisors is an integer number (124007130).

Almost surely, 2^640036784 is an apocalyptic number.

It is an amenable number.

640036784 is a deficient number, since it is larger than the sum of its proper divisors (600034516).

640036784 is a wasteful number, since it uses less digits than its factorization.

640036784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40002307 (or 40002301 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 640036784 is about 25298.9482785352. The cubic root of 640036784 is about 861.7903858476.

The spelling of 640036784 in words is "six hundred forty million, thirty-six thousand, seven hundred eighty-four".