81473391 has 16 divisors (see below), whose sum is σ = 121237600. Its totient is φ = 54074304.

The previous prime is 81473389. The next prime is 81473393. The reversal of 81473391 is 19337418.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81473389) and next prime (81473393).

It is not a de Polignac number, because 81473391 - 2¹ = 81473389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81473393) 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, 406 + ... + 12771.

It is an arithmetic number, because the mean of its divisors is an integer number (7577350).

Almost surely, 2^81473391 is an apocalyptic number.

81473391 is a deficient number, since it is larger than the sum of its proper divisors (39764209).

81473391 is a wasteful number, since it uses less digits than its factorization.

81473391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13415 (or 13409 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 81473391 is about 9026.2611861169. The cubic root of 81473391 is about 433.5161330666.

The spelling of 81473391 in words is "eighty-one million, four hundred seventy-three thousand, three hundred ninety-one".