640055539 has 4 divisors (see below), whose sum is σ = 643755456. Its totient is φ = 636355624.

The previous prime is 640055497. The next prime is 640055587. The reversal of 640055539 is 935550046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640055539 - 2⁷ = 640055411 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640055498 and 640055507.

It is not an unprimeable number, because it can be changed into a prime (640055239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1849699 + ... + 1850044.

It is an arithmetic number, because the mean of its divisors is an integer number (160938864).

Almost surely, 2^640055539 is an apocalyptic number.

640055539 is a deficient number, since it is larger than the sum of its proper divisors (3699917).

640055539 is a wasteful number, since it uses less digits than its factorization.

640055539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3699916.

The product of its (nonzero) digits is 81000, while the sum is 37.

The square root of 640055539 is about 25299.3189434024. The cubic root of 640055539 is about 861.7988034476.

The spelling of 640055539 in words is "six hundred forty million, fifty-five thousand, five hundred thirty-nine".