81616895 has 4 divisors (see below), whose sum is σ = 97940280. Its totient is φ = 65293512.

The previous prime is 81616889. The next prime is 81616897. The reversal of 81616895 is 59861618.

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 81616895 - 2⁴ = 81616879 is a prime.

It is a super-2 number, since 2×81616895² = 13322635098882050, which contains 22 as substring.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81616897) 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, 8161685 + ... + 8161694.

It is an arithmetic number, because the mean of its divisors is an integer number (24485070).

Almost surely, 2^81616895 is an apocalyptic number.

81616895 is a deficient number, since it is larger than the sum of its proper divisors (16323385).

81616895 is a wasteful number, since it uses less digits than its factorization.

81616895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16323384.

The product of its digits is 103680, while the sum is 44.

The square root of 81616895 is about 9034.2069380771. The cubic root of 81616895 is about 433.7705098170.

The spelling of 81616895 in words is "eighty-one million, six hundred sixteen thousand, eight hundred ninety-five".