81125370031 has 4 divisors (see below), whose sum is σ = 81489161152. Its totient is φ = 80761578912.

The previous prime is 81125369993. The next prime is 81125370049. The reversal of 81125370031 is 13007352118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81125370031 - 2⁹ = 81125369519 is a prime.

It is a super-2 number, since 2×81125370031² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81125369975 and 81125370002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81125370071) 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, 181895226 + ... + 181895671.

It is an arithmetic number, because the mean of its divisors is an integer number (20372290288).

Almost surely, 2^81125370031 is an apocalyptic number.

81125370031 is a deficient number, since it is larger than the sum of its proper divisors (363791121).

81125370031 is a wasteful number, since it uses less digits than its factorization.

81125370031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363791120.

The product of its (nonzero) digits is 5040, while the sum is 31.

The spelling of 81125370031 in words is "eighty-one billion, one hundred twenty-five million, three hundred seventy thousand, thirty-one".