640620454 has 16 divisors (see below), whose sum is σ = 1012880880. Its totient is φ = 303039360.

The previous prime is 640620451. The next prime is 640620509. The reversal of 640620454 is 454026046.

It is a super-2 number, since 2×640620454² = 820789132166332232, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640620451) 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, 17842 + ... + 39994.

It is an arithmetic number, because the mean of its divisors is an integer number (63305055).

Almost surely, 2^640620454 is an apocalyptic number.

640620454 is a deficient number, since it is larger than the sum of its proper divisors (372260426).

640620454 is a wasteful number, since it uses less digits than its factorization.

640620454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22935.

The product of its (nonzero) digits is 23040, while the sum is 31.

The square root of 640620454 is about 25310.4811096115. The cubic root of 640620454 is about 862.0522709890.

The spelling of 640620454 in words is "six hundred forty million, six hundred twenty thousand, four hundred fifty-four".