643405531131 has 24 divisors (see below), whose sum is σ = 1018397592576. Its totient is φ = 388194110640.

The previous prime is 643405531117. The next prime is 643405531141. The reversal of 643405531131 is 131135504346.

643405531131 is a `hidden beast` number, since 64 + 3 + 4 + 0 + 553 + 11 + 31 = 666.

It is not a de Polignac number, because 643405531131 - 2⁷ = 643405531003 is a prime.

It is a super-3 number, since 3×643405531131³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (643405531141) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14549775 + ... + 14593928.

It is an arithmetic number, because the mean of its divisors is an integer number (42433233024).

Almost surely, 2^643405531131 is an apocalyptic number.

643405531131 is a deficient number, since it is larger than the sum of its proper divisors (374992061445).

643405531131 is a wasteful number, since it uses less digits than its factorization.

643405531131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29143943 (or 29143940 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The spelling of 643405531131 in words is "six hundred forty-three billion, four hundred five million, five hundred thirty-one thousand, one hundred thirty-one".