81479640534 has 12 divisors (see below), whose sum is σ = 162960679476. Its totient is φ = 27159647112.

The previous prime is 81479640511. The next prime is 81479640569. The reversal of 81479640534 is 43504697418.

It is a happy number.

It is a super-3 number, since 3×81479640534³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 640932 + ... + 757464.

It is an arithmetic number, because the mean of its divisors is an integer number (13580056623).

Almost surely, 2^81479640534 is an apocalyptic number.

81479640534 is an abundant number, since it is smaller than the sum of its proper divisors (81481038942).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81479640534 is an frugal number, since it uses more digits than its factorization.

81479640534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233071 (or 116538 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 81479640534 in words is "eighty-one billion, four hundred seventy-nine million, six hundred forty thousand, five hundred thirty-four".