640454431 has 8 divisors (see below), whose sum is σ = 648172784. Its totient is φ = 632759040.

The previous prime is 640454417. The next prime is 640454449. The reversal of 640454431 is 134454046.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640454431 is a prime.

It is a super-2 number, since 2×640454431² = 820363756375067522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640454393 and 640454402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640454401) 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, 54076 + ... + 64846.

It is an arithmetic number, because the mean of its divisors is an integer number (81021598).

Almost surely, 2^640454431 is an apocalyptic number.

640454431 is a deficient number, since it is larger than the sum of its proper divisors (7718353).

640454431 is a wasteful number, since it uses less digits than its factorization.

640454431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11481.

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

The square root of 640454431 is about 25307.2011688373. The cubic root of 640454431 is about 861.9777948210.

The spelling of 640454431 in words is "six hundred forty million, four hundred fifty-four thousand, four hundred thirty-one".