81619231 has 8 divisors (see below), whose sum is σ = 86326400. Its totient is φ = 76953240.

The previous prime is 81619207. The next prime is 81619273. The reversal of 81619231 is 13291618.

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

It is a cyclic number.

It is not a de Polignac number, because 81619231 - 2⁷ = 81619103 is a prime.

It is a super-2 number, since 2×81619231² = 13323397738062722, 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 = 81619193 and 81619202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81619331) 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, 6171 + ... + 14188.

It is an arithmetic number, because the mean of its divisors is an integer number (10790800).

Almost surely, 2^81619231 is an apocalyptic number.

81619231 is a deficient number, since it is larger than the sum of its proper divisors (4707169).

81619231 is a wasteful number, since it uses less digits than its factorization.

81619231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20589.

The product of its digits is 2592, while the sum is 31.

The square root of 81619231 is about 9034.3362235418. The cubic root of 81619231 is about 433.7746481687.

The spelling of 81619231 in words is "eighty-one million, six hundred nineteen thousand, two hundred thirty-one".