643451431 has 8 divisors (see below), whose sum is σ = 737770880. Its totient is φ = 549731448.

The previous prime is 643451387. The next prime is 643451437. The reversal of 643451431 is 134154346.

It is a happy number.

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

It is not a de Polignac number, because 643451431 - 2¹⁵ = 643418663 is a prime.

It is a super-2 number, since 2×643451431² = 828059488111895522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 643451393 and 643451402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643451437) 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, 147561 + ... + 151858.

It is an arithmetic number, because the mean of its divisors is an integer number (92221360).

Almost surely, 2^643451431 is an apocalyptic number.

643451431 is a deficient number, since it is larger than the sum of its proper divisors (94319449).

643451431 is a wasteful number, since it uses less digits than its factorization.

643451431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299733.

The product of its digits is 17280, while the sum is 31.

The square root of 643451431 is about 25366.3444548086. The cubic root of 643451431 is about 863.3202417809.

The spelling of 643451431 in words is "six hundred forty-three million, four hundred fifty-one thousand, four hundred thirty-one".