81997677 has 24 divisors (see below), whose sum is σ = 123841536. Its totient is φ = 54214272.

The previous prime is 81997667. The next prime is 81997679. The reversal of 81997677 is 77679918.

It is not a de Polignac number, because 81997677 - 2¹⁰ = 81996653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81997679) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29533 + ... + 32189.

It is an arithmetic number, because the mean of its divisors is an integer number (5160064).

Almost surely, 2^81997677 is an apocalyptic number.

It is an amenable number.

81997677 is a deficient number, since it is larger than the sum of its proper divisors (41843859).

81997677 is a wasteful number, since it uses less digits than its factorization.

81997677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2799 (or 2787 counting only the distinct ones).

The product of its digits is 1333584, while the sum is 54.

The square root of 81997677 is about 9055.2568710114. The cubic root of 81997677 is about 434.4440460054. Note that the first 3 decimals are identical.

It can be divided in two parts, 8199 and 7677, that added together give a square (15876 = 126²).

The spelling of 81997677 in words is "eighty-one million, nine hundred ninety-seven thousand, six hundred seventy-seven".