81397169 has 16 divisors (see below), whose sum is σ = 94924800. Its totient is φ = 68357520.

The previous prime is 81397163. The next prime is 81397181. The reversal of 81397169 is 96179318.

It is not a de Polignac number, because 81397169 - 2⁴ = 81397153 is a prime.

It is a super-2 number, since 2×81397169² = 13250998242429122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81397163) 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, 98492 + ... + 99314.

It is an arithmetic number, because the mean of its divisors is an integer number (5932800).

Almost surely, 2^81397169 is an apocalyptic number.

It is an amenable number.

81397169 is a deficient number, since it is larger than the sum of its proper divisors (13527631).

81397169 is a wasteful number, since it uses less digits than its factorization.

81397169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100.

The product of its digits is 81648, while the sum is 44.

The square root of 81397169 is about 9022.0379626778. The cubic root of 81397169 is about 433.3808996438.

The spelling of 81397169 in words is "eighty-one million, three hundred ninety-seven thousand, one hundred sixty-nine".