81280631 has 4 divisors (see below), whose sum is σ = 81446664. Its totient is φ = 81114600.

The previous prime is 81280607. The next prime is 81280681. The reversal of 81280631 is 13608218.

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 81280631 - 2²⁶ = 14171767 is a prime.

It is a super-2 number, since 2×81280631² = 13213081951516322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81280594 and 81280603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81280681) 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, 82280 + ... + 83261.

It is an arithmetic number, because the mean of its divisors is an integer number (20361666).

Almost surely, 2^81280631 is an apocalyptic number.

81280631 is a deficient number, since it is larger than the sum of its proper divisors (166033).

81280631 is a wasteful number, since it uses less digits than its factorization.

81280631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166032.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 81280631 is about 9015.5771307221. The cubic root of 81280631 is about 433.1739740784.

Adding to 81280631 its reverse (13608218), we get a palindrome (94888849).

The spelling of 81280631 in words is "eighty-one million, two hundred eighty thousand, six hundred thirty-one".