640621662 has 16 divisors (see below), whose sum is σ = 1281505152. Its totient is φ = 213496920.

The previous prime is 640621649. The next prime is 640621669. The reversal of 640621662 is 266126046.

It is a super-2 number, since 2×640621662² = 820792227647284488, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640621669) 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, 37263 + ... + 51669.

It is an arithmetic number, because the mean of its divisors is an integer number (80094072).

Almost surely, 2^640621662 is an apocalyptic number.

640621662 is an abundant number, since it is smaller than the sum of its proper divisors (640883490).

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

640621662 is a wasteful number, since it uses less digits than its factorization.

640621662 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21823.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 640621662 is about 25310.5049732320. The cubic root of 640621662 is about 862.0528128379.

The spelling of 640621662 in words is "six hundred forty million, six hundred twenty-one thousand, six hundred sixty-two".