640901607 has 8 divisors (see below), whose sum is σ = 854813040. Its totient is φ = 427128960.

The previous prime is 640901587. The next prime is 640901609. The reversal of 640901607 is 706109046.

It is a happy number.

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

It is not a de Polignac number, because 640901607 - 2⁶ = 640901543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640901609) 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, 23394 + ... + 42767.

It is an arithmetic number, because the mean of its divisors is an integer number (106851630).

Almost surely, 2^640901607 is an apocalyptic number.

640901607 is a deficient number, since it is larger than the sum of its proper divisors (213911433).

640901607 is a wasteful number, since it uses less digits than its factorization.

640901607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69393.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 640901607 is about 25316.0345828489. The cubic root of 640901607 is about 862.1783639211.

The spelling of 640901607 in words is "six hundred forty million, nine hundred one thousand, six hundred seven".