640606501 has 4 divisors (see below), whose sum is σ = 641673004. Its totient is φ = 639540000.

The previous prime is 640606481. The next prime is 640606507. The reversal of 640606501 is 105606046.

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

It can be written as a sum of positive squares in 2 ways, for example, as 578354401 + 62252100 = 24049^2 + 7890^2 .

It is a cyclic number.

It is not a de Polignac number, because 640606501 - 2¹⁹ = 640082213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640606501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640606507) 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, 532350 + ... + 533551.

It is an arithmetic number, because the mean of its divisors is an integer number (160418251).

Almost surely, 2^640606501 is an apocalyptic number.

It is an amenable number.

640606501 is a deficient number, since it is larger than the sum of its proper divisors (1066503).

640606501 is a wasteful number, since it uses less digits than its factorization.

640606501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1066502.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 640606501 is about 25310.2054713114. The cubic root of 640606501 is about 862.0460123156.

The spelling of 640606501 in words is "six hundred forty million, six hundred six thousand, five hundred one".