643457131 has 4 divisors (see below), whose sum is σ = 671433552. Its totient is φ = 615480712.

The previous prime is 643457107. The next prime is 643457137. The reversal of 643457131 is 131754346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 131754346 = 2 ⋅65877173.

It is a cyclic number.

It is not a de Polignac number, because 643457131 - 2²³ = 635068523 is a prime.

It is a super-3 number, since 3×643457131³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643457137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13988176 + ... + 13988221.

It is an arithmetic number, because the mean of its divisors is an integer number (167858388).

Almost surely, 2^643457131 is an apocalyptic number.

643457131 is a deficient number, since it is larger than the sum of its proper divisors (27976421).

643457131 is a wasteful number, since it uses less digits than its factorization.

643457131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27976420.

The product of its digits is 30240, while the sum is 34.

The square root of 643457131 is about 25366.4568081551. The cubic root of 643457131 is about 863.3227910077.

The spelling of 643457131 in words is "six hundred forty-three million, four hundred fifty-seven thousand, one hundred thirty-one".