640218275 has 6 divisors (see below), whose sum is σ = 793870692. Its totient is φ = 512174600.

The previous prime is 640218269. The next prime is 640218287. The reversal of 640218275 is 572812046.

It is not a de Polignac number, because 640218275 - 2¹⁸ = 639956131 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12804341 + ... + 12804390.

It is an arithmetic number, because the mean of its divisors is an integer number (132311782).

Almost surely, 2^640218275 is an apocalyptic number.

640218275 is a deficient number, since it is larger than the sum of its proper divisors (153652417).

640218275 is a wasteful number, since it uses less digits than its factorization.

640218275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25608741 (or 25608736 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 640218275 is about 25302.5349520557. The cubic root of 640218275 is about 861.8718355504.

The spelling of 640218275 in words is "six hundred forty million, two hundred eighteen thousand, two hundred seventy-five".