81378297 has 64 divisors (see below), whose sum is σ = 161925120. Its totient is φ = 39009600.

The previous prime is 81378289. The next prime is 81378299. The reversal of 81378297 is 79287318.

It is not a de Polignac number, because 81378297 - 2³ = 81378289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81378299) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 25522 + ... + 28532.

It is an arithmetic number, because the mean of its divisors is an integer number (2530080).

Almost surely, 2^81378297 is an apocalyptic number.

It is an amenable number.

81378297 is a deficient number, since it is larger than the sum of its proper divisors (80546823).

81378297 is a wasteful number, since it uses less digits than its factorization.

81378297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3051 (or 3045 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 81378297 is about 9020.9920186197. The cubic root of 81378297 is about 433.3474038166.

The spelling of 81378297 in words is "eighty-one million, three hundred seventy-eight thousand, two hundred ninety-seven".