81898797 has 16 divisors (see below), whose sum is σ = 118055360. Its totient is φ = 50326272.

The previous prime is 81898787. The next prime is 81898811. The reversal of 81898797 is 79789818.

It is not a de Polignac number, because 81898797 - 2⁴ = 81898781 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81898777) 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, 17308 + ... + 21525.

It is an arithmetic number, because the mean of its divisors is an integer number (7378460).

Almost surely, 2^81898797 is an apocalyptic number.

It is an amenable number.

81898797 is a deficient number, since it is larger than the sum of its proper divisors (36156563).

81898797 is a wasteful number, since it uses less digits than its factorization.

81898797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38892.

The product of its digits is 2032128, while the sum is 57.

The square root of 81898797 is about 9049.7954120521. The cubic root of 81898797 is about 434.2693455023.

The spelling of 81898797 in words is "eighty-one million, eight hundred ninety-eight thousand, seven hundred ninety-seven".