640277628 has 24 divisors (see below), whose sum is σ = 1494402000. Its totient is φ = 213365760.

The previous prime is 640277623. The next prime is 640277629. The reversal of 640277628 is 826772046.

It is a self number, because there is not a number n which added to its sum of digits gives 640277628.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640277623) 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, 64348 + ... + 73628.

It is an arithmetic number, because the mean of its divisors is an integer number (62266750).

Almost surely, 2^640277628 is an apocalyptic number.

It is an amenable number.

640277628 is an abundant number, since it is smaller than the sum of its proper divisors (854124372).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640277628 is a wasteful number, since it uses less digits than its factorization.

640277628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15037 (or 15035 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 42.

The square root of 640277628 is about 25303.7077915471. The cubic root of 640277628 is about 861.8984687058.

The spelling of 640277628 in words is "six hundred forty million, two hundred seventy-seven thousand, six hundred twenty-eight".