81135667723 has 16 divisors (see below), whose sum is σ = 89126578944. Its totient is φ = 73248896160.

The previous prime is 81135667709. The next prime is 81135667771. The reversal of 81135667723 is 32776653118.

It is not a de Polignac number, because 81135667723 - 2³³ = 72545733131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81135667703) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 950386 + ... + 1032232.

It is an arithmetic number, because the mean of its divisors is an integer number (5570411184).

Almost surely, 2^81135667723 is an apocalyptic number.

81135667723 is a deficient number, since it is larger than the sum of its proper divisors (7990911221).

81135667723 is a wasteful number, since it uses less digits than its factorization.

81135667723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82482.

The product of its digits is 1270080, while the sum is 49.

The spelling of 81135667723 in words is "eighty-one billion, one hundred thirty-five million, six hundred sixty-seven thousand, seven hundred twenty-three".