81431028 has 48 divisors (see below), whose sum is σ = 241279360. Its totient is φ = 23265792.

The previous prime is 81431027. The next prime is 81431039. The reversal of 81431028 is 82013418.

It is a super-2 number, since 2×81431028² = 13262024642273568, 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 = 81430992 and 81431010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81431023) 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, 53101 + ... + 54612.

Almost surely, 2^81431028 is an apocalyptic number.

It is an amenable number.

81431028 is an abundant number, since it is smaller than the sum of its proper divisors (159848332).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81431028 is a wasteful number, since it uses less digits than its factorization.

81431028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107733 (or 107725 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81431028 is about 9023.9142283158. The cubic root of 81431028 is about 433.4409828542.

The spelling of 81431028 in words is "eighty-one million, four hundred thirty-one thousand, twenty-eight".