81642120524 has 12 divisors (see below), whose sum is σ = 142878092448. Its totient is φ = 40819808400.

The previous prime is 81642120517. The next prime is 81642120529. The reversal of 81642120524 is 42502124618.

It is not an unprimeable number, because it can be changed into a prime (81642120529) 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, 157667 + ... + 433754.

It is an arithmetic number, because the mean of its divisors is an integer number (11906507704).

Almost surely, 2^81642120524 is an apocalyptic number.

It is an amenable number.

81642120524 is a deficient number, since it is larger than the sum of its proper divisors (61235971924).

81642120524 is a wasteful number, since it uses less digits than its factorization.

81642120524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625936 (or 625934 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 35.

The spelling of 81642120524 in words is "eighty-one billion, six hundred forty-two million, one hundred twenty thousand, five hundred twenty-four".