81411831 has 16 divisors (see below), whose sum is σ = 121137120. Its totient is φ = 54037440.

The previous prime is 81411823. The next prime is 81411851. The reversal of 81411831 is 13811418.

It is not a de Polignac number, because 81411831 - 2³ = 81411823 is a prime.

It is a super-2 number, since 2×81411831² = 13255772453545122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 81411795 and 81411804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81411821) 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, 180 + ... + 12761.

It is an arithmetic number, because the mean of its divisors is an integer number (7571070).

Almost surely, 2^81411831 is an apocalyptic number.

81411831 is a deficient number, since it is larger than the sum of its proper divisors (39725289).

81411831 is a wasteful number, since it uses less digits than its factorization.

81411831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13183 (or 13177 counting only the distinct ones).

The product of its digits is 768, while the sum is 27.

The square root of 81411831 is about 9022.8504919454. The cubic root of 81411831 is about 433.4069195874.

The spelling of 81411831 in words is "eighty-one million, four hundred eleven thousand, eight hundred thirty-one".