640677140 has 24 divisors (see below), whose sum is σ = 1346467752. Its totient is φ = 256071680.

The previous prime is 640677137. The next prime is 640677157. The reversal of 640677140 is 41776046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1800964 + 638876176 = 1342^2 + 25276^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640677140.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15452 + ... + 38988.

It is an arithmetic number, because the mean of its divisors is an integer number (56102823).

Almost surely, 2^640677140 is an apocalyptic number.

It is an amenable number.

640677140 is an abundant number, since it is smaller than the sum of its proper divisors (705790612).

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

640677140 is a wasteful number, since it uses less digits than its factorization.

640677140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24907 (or 24905 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 35.

The square root of 640677140 is about 25311.6008976121. The cubic root of 640677140 is about 862.0776967844.

The spelling of 640677140 in words is "six hundred forty million, six hundred seventy-seven thousand, one hundred forty".