81138827 has 16 divisors (see below), whose sum is σ = 101606400. Its totient is φ = 62946240.

The previous prime is 81138821. The next prime is 81138829. The reversal of 81138827 is 72883118.

It is not a de Polignac number, because 81138827 - 2²⁰ = 80090251 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81138821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16199 + ... + 20607.

It is an arithmetic number, because the mean of its divisors is an integer number (6350400).

Almost surely, 2^81138827 is an apocalyptic number.

81138827 is a deficient number, since it is larger than the sum of its proper divisors (20467573).

81138827 is a wasteful number, since it uses less digits than its factorization.

81138827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4666.

The product of its digits is 21504, while the sum is 38.

The square root of 81138827 is about 9007.7093092528. The cubic root of 81138827 is about 432.9219191187.

The spelling of 81138827 in words is "eighty-one million, one hundred thirty-eight thousand, eight hundred twenty-seven".