81634503123 has 24 divisors (see below), whose sum is σ = 119881731840. Its totient is φ = 53516453760.

The previous prime is 81634503113. The next prime is 81634503127. The reversal of 81634503123 is 32130543618.

81634503123 is a `hidden beast` number, since 8 + 1 + 634 + 5 + 0 + 3 + 12 + 3 = 666.

It is not a de Polignac number, because 81634503123 - 2⁵ = 81634503091 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81634503127) 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, 2265415 + ... + 2301167.

It is an arithmetic number, because the mean of its divisors is an integer number (4995072160).

Almost surely, 2^81634503123 is an apocalyptic number.

81634503123 is a deficient number, since it is larger than the sum of its proper divisors (38247228717).

81634503123 is a wasteful number, since it uses less digits than its factorization.

81634503123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39979 (or 39976 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 81634503123 in words is "eighty-one billion, six hundred thirty-four million, five hundred three thousand, one hundred twenty-three".