640000537 has 4 divisors (see below), whose sum is σ = 698182416. Its totient is φ = 581818660.

The previous prime is 640000531. The next prime is 640000583. The reversal of 640000537 is 735000046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640000537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640000531) 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, 29090923 + ... + 29090944.

It is an arithmetic number, because the mean of its divisors is an integer number (174545604).

Almost surely, 2^640000537 is an apocalyptic number.

It is an amenable number.

640000537 is a deficient number, since it is larger than the sum of its proper divisors (58181879).

640000537 is a wasteful number, since it uses less digits than its factorization.

640000537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58181878.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 640000537 is about 25298.2318947392. The cubic root of 640000537 is about 861.7741170401.

The spelling of 640000537 in words is "six hundred forty million, five hundred thirty-seven", and thus it is an aban number.