81616233 has 4 divisors (see below), whose sum is σ = 108821648. Its totient is φ = 54410820.

The previous prime is 81616217. The next prime is 81616247. The reversal of 81616233 is 33261618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81616233 - 2⁴ = 81616217 is a prime.

It is a super-2 number, since 2×81616233² = 13322418978220578, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81616233.

It is not an unprimeable number, because it can be changed into a prime (81616253) 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, 13602703 + ... + 13602708.

It is an arithmetic number, because the mean of its divisors is an integer number (27205412).

Almost surely, 2^81616233 is an apocalyptic number.

It is an amenable number.

81616233 is a deficient number, since it is larger than the sum of its proper divisors (27205415).

81616233 is a wasteful number, since it uses less digits than its factorization.

81616233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27205414.

The product of its digits is 5184, while the sum is 30.

The square root of 81616233 is about 9034.1702994796. The cubic root of 81616233 is about 433.7693370335.

The spelling of 81616233 in words is "eighty-one million, six hundred sixteen thousand, two hundred thirty-three".