81117651 has 8 divisors (see below), whose sum is σ = 110672320. Its totient is φ = 52820712.

The previous prime is 81117649. The next prime is 81117679. The reversal of 81117651 is 15671118.

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

It is not a de Polignac number, because 81117651 - 2¹ = 81117649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81117601) 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, 314281 + ... + 314538.

It is an arithmetic number, because the mean of its divisors is an integer number (13834040).

Almost surely, 2^81117651 is an apocalyptic number.

81117651 is a deficient number, since it is larger than the sum of its proper divisors (29554669).

81117651 is a wasteful number, since it uses less digits than its factorization.

81117651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628865.

The product of its digits is 1680, while the sum is 30.

The square root of 81117651 is about 9006.5337949735. The cubic root of 81117651 is about 432.8842538293.

Adding to 81117651 its reverse (15671118), we get a palindrome (96788769).

The spelling of 81117651 in words is "eighty-one million, one hundred seventeen thousand, six hundred fifty-one".