640454551 has 8 divisors (see below), whose sum is σ = 699609744. Its totient is φ = 581454720.

The previous prime is 640454539. The next prime is 640454557. The reversal of 640454551 is 155454046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640454551 - 2¹⁵ = 640421783 is a prime.

It is a super-2 number, since 2×640454551² = 820364063793223202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640454557) 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, 30130 + ... + 46783.

It is an arithmetic number, because the mean of its divisors is an integer number (87451218).

Almost surely, 2^640454551 is an apocalyptic number.

640454551 is a deficient number, since it is larger than the sum of its proper divisors (59155193).

640454551 is a wasteful number, since it uses less digits than its factorization.

640454551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77681.

The product of its (nonzero) digits is 48000, while the sum is 34.

The square root of 640454551 is about 25307.2035397039. The cubic root of 640454551 is about 861.9778486564.

The spelling of 640454551 in words is "six hundred forty million, four hundred fifty-four thousand, five hundred fifty-one".