640670501 has 4 divisors (see below), whose sum is σ = 644913504. Its totient is φ = 636427500.

The previous prime is 640670491. The next prime is 640670507. The reversal of 640670501 is 105076046.

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, and also an emirpimes, since its reverse is a distinct semiprime: 105076046 = 2 ⋅52538023.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640670501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640670507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2121275 + ... + 2121576.

It is an arithmetic number, because the mean of its divisors is an integer number (161228376).

Almost surely, 2^640670501 is an apocalyptic number.

It is an amenable number.

640670501 is a deficient number, since it is larger than the sum of its proper divisors (4243003).

640670501 is a wasteful number, since it uses less digits than its factorization.

640670501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4243002.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 640670501 is about 25311.4697518734. The cubic root of 640670501 is about 862.0747190216.

The spelling of 640670501 in words is "six hundred forty million, six hundred seventy thousand, five hundred one".