81350031 has 8 divisors (see below), whose sum is σ = 123961984. Its totient is φ = 46485720.

The previous prime is 81349991. The next prime is 81350033. The reversal of 81350031 is 13005318.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81350031 - 2¹⁰ = 81349007 is a prime.

It is a super-2 number, since 2×81350031² = 13235655087401922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 3873811 = 81350031 / (8 + 1 + 3 + 5 + 0 + 0 + 3 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81350033) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1936885 + ... + 1936926.

It is an arithmetic number, because the mean of its divisors is an integer number (15495248).

Almost surely, 2^81350031 is an apocalyptic number.

81350031 is a deficient number, since it is larger than the sum of its proper divisors (42611953).

81350031 is a wasteful number, since it uses less digits than its factorization.

81350031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3873821.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 81350031 is about 9019.4252034151. The cubic root of 81350031 is about 433.2972249334.

Adding to 81350031 its reverse (13005318), we get a palindrome (94355349).

The spelling of 81350031 in words is "eighty-one million, three hundred fifty thousand, thirty-one".