81222831 has 10 divisors (see below), whose sum is σ = 121332992. Its totient is φ = 54148500.

The previous prime is 81222809. The next prime is 81222859. The reversal of 81222831 is 13822218.

It is not a de Polignac number, because 81222831 - 2⁷ = 81222703 is a prime.

It is a super-2 number, since 2×81222831² = 13194296551309122, which contains 22 as substring.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81222795 and 81222804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81222431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 501295 + ... + 501456.

Almost surely, 2^81222831 is an apocalyptic number.

81222831 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81222831 is a deficient number, since it is larger than the sum of its proper divisors (40110161).

81222831 is a wasteful number, since it uses less digits than its factorization.

81222831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002763 (or 1002754 counting only the distinct ones).

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

The square root of 81222831 is about 9012.3709976898. The cubic root of 81222831 is about 433.0712706725.

The spelling of 81222831 in words is "eighty-one million, two hundred twenty-two thousand, eight hundred thirty-one".