81162631 has 4 divisors (see below), whose sum is σ = 88541064. Its totient is φ = 73784200.

The previous prime is 81162611. The next prime is 81162637. The reversal of 81162631 is 13626118.

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 81162631 - 2¹³ = 81154439 is a prime.

It is a super-2 number, since 2×81162631² = 13174745341684322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81162631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81162637) 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, 3689200 + ... + 3689221.

It is an arithmetic number, because the mean of its divisors is an integer number (22135266).

Almost surely, 2^81162631 is an apocalyptic number.

81162631 is a deficient number, since it is larger than the sum of its proper divisors (7378433).

81162631 is a wasteful number, since it uses less digits than its factorization.

81162631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7378432.

The product of its digits is 1728, while the sum is 28.

The square root of 81162631 is about 9009.0305249788. The cubic root of 81162631 is about 432.9642509515.

Adding to 81162631 its reverse (13626118), we get a palindrome (94788749).

The spelling of 81162631 in words is "eighty-one million, one hundred sixty-two thousand, six hundred thirty-one".