81336397 has 24 divisors (see below), whose sum is σ = 91173600. Its totient is φ = 72311616.

The previous prime is 81336391. The next prime is 81336401. The reversal of 81336397 is 79363318.

It is not a de Polignac number, because 81336397 - 2³ = 81336389 is a prime.

It is a Duffinian number.

Its product of digits (81648) is a multiple of the sum of its prime divisors (168).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81336391) 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, 1378554 + ... + 1378612.

It is an arithmetic number, because the mean of its divisors is an integer number (3798900).

Almost surely, 2^81336397 is an apocalyptic number.

It is an amenable number.

81336397 is a deficient number, since it is larger than the sum of its proper divisors (9837203).

81336397 is a wasteful number, since it uses less digits than its factorization.

81336397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 168 counting only the distinct ones).

The product of its digits is 81648, while the sum is 40.

The square root of 81336397 is about 9018.6693586138. The cubic root of 81336397 is about 433.2730171802.

The spelling of 81336397 in words is "eighty-one million, three hundred thirty-six thousand, three hundred ninety-seven".