81501431 has 16 divisors (see below), whose sum is σ = 95592960. Its totient is φ = 68690880.

The previous prime is 81501421. The next prime is 81501463. The reversal of 81501431 is 13410518.

It is a cyclic number.

It is not a de Polignac number, because 81501431 - 2⁶ = 81501367 is a prime.

It is a super-2 number, since 2×81501431² = 13284966510095522, 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 = 81501397 and 81501406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81501401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5675 + ... + 13971.

It is an arithmetic number, because the mean of its divisors is an integer number (5974560).

Almost surely, 2^81501431 is an apocalyptic number.

81501431 is a deficient number, since it is larger than the sum of its proper divisors (14091529).

81501431 is a wasteful number, since it uses less digits than its factorization.

81501431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8374.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 81501431 is about 9027.8142980458. The cubic root of 81501431 is about 433.5658605419.

Adding to 81501431 its reverse (13410518), we get a palindrome (94911949).

The spelling of 81501431 in words is "eighty-one million, five hundred one thousand, four hundred thirty-one".