640661510 has 16 divisors (see below), whose sum is σ = 1153481472. Its totient is φ = 256200000.

The previous prime is 640661501. The next prime is 640661519. The reversal of 640661510 is 15166046.

It is an interprime number because it is at equal distance from previous prime (640661501) and next prime (640661519).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640661519) 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, 65435 + ... + 74585.

It is an arithmetic number, because the mean of its divisors is an integer number (72092592).

Almost surely, 2^640661510 is an apocalyptic number.

640661510 is a deficient number, since it is larger than the sum of its proper divisors (512819962).

640661510 is a wasteful number, since it uses less digits than its factorization.

640661510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16159.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 640661510 is about 25311.2921440214. The cubic root of 640661510 is about 862.0706862934.

The spelling of 640661510 in words is "six hundred forty million, six hundred sixty-one thousand, five hundred ten".