640259955 has 24 divisors (see below), whose sum is σ = 1114648080. Its totient is φ = 339975360.

The previous prime is 640259953. The next prime is 640259987. The reversal of 640259955 is 559952046.

It is a happy number.

640259955 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 599 + 55 = 666.

It is not a de Polignac number, because 640259955 - 2¹ = 640259953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 640259955.

It is not an unprimeable number, because it can be changed into a prime (640259953) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20761 + ... + 41370.

It is an arithmetic number, because the mean of its divisors is an integer number (46443670).

Almost surely, 2^640259955 is an apocalyptic number.

640259955 is a deficient number, since it is larger than the sum of its proper divisors (474388125).

640259955 is a wasteful number, since it uses less digits than its factorization.

640259955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62371 (or 62368 counting only the distinct ones).

The product of its (nonzero) digits is 486000, while the sum is 45.

The square root of 640259955 is about 25303.3585715414. The cubic root of 640259955 is about 861.8905385667.

The spelling of 640259955 in words is "six hundred forty million, two hundred fifty-nine thousand, nine hundred fifty-five".