640680087 has 8 divisors (see below), whose sum is σ = 854383104. Its totient is φ = 427048568.

The previous prime is 640680083. The next prime is 640680101. The reversal of 640680087 is 780086046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640680087 - 2² = 640680083 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640680083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8668 + ... + 36830.

It is an arithmetic number, because the mean of its divisors is an integer number (106797888).

Almost surely, 2^640680087 is an apocalyptic number.

640680087 is a deficient number, since it is larger than the sum of its proper divisors (213703017).

640680087 is a wasteful number, since it uses less digits than its factorization.

640680087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35749.

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 640680087 is about 25311.6591119587. The cubic root of 640680087 is about 862.0790185833.

The spelling of 640680087 in words is "six hundred forty million, six hundred eighty thousand, eighty-seven".