81616963 has 4 divisors (see below), whose sum is σ = 82955008. Its totient is φ = 80278920.

The previous prime is 81616961. The next prime is 81616973. The reversal of 81616963 is 36961618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36961618 = 2 ⋅18480809.

It is a cyclic number.

It is not a de Polignac number, because 81616963 - 2¹ = 81616961 is a prime.

It is a super-2 number, since 2×81616963² = 13322657298686738, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81616961) 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, 668931 + ... + 669052.

It is an arithmetic number, because the mean of its divisors is an integer number (20738752).

Almost surely, 2^81616963 is an apocalyptic number.

81616963 is a deficient number, since it is larger than the sum of its proper divisors (1338045).

81616963 is a wasteful number, since it uses less digits than its factorization.

81616963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1338044.

The product of its digits is 46656, while the sum is 40.

The square root of 81616963 is about 9034.2107015500. The cubic root of 81616963 is about 433.7706302839.

The spelling of 81616963 in words is "eighty-one million, six hundred sixteen thousand, nine hundred sixty-three".