81382631 has 4 divisors (see below), whose sum is σ = 88781064. Its totient is φ = 73984200.

The previous prime is 81382627. The next prime is 81382667. The reversal of 81382631 is 13628318.

It is a happy number.

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 81382631 - 2² = 81382627 is a prime.

It is a super-2 number, since 2×81382631² = 13246265256964322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81382031) 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, 3699200 + ... + 3699221.

It is an arithmetic number, because the mean of its divisors is an integer number (22195266).

Almost surely, 2^81382631 is an apocalyptic number.

81382631 is a deficient number, since it is larger than the sum of its proper divisors (7398433).

81382631 is a wasteful number, since it uses less digits than its factorization.

81382631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7398432.

The product of its digits is 6912, while the sum is 32.

The square root of 81382631 is about 9021.2322329048. The cubic root of 81382631 is about 433.3550966716.

The spelling of 81382631 in words is "eighty-one million, three hundred eighty-two thousand, six hundred thirty-one".