81897874 has 8 divisors (see below), whose sum is σ = 130073148. Its totient is φ = 38540160.

The previous prime is 81897863. The next prime is 81897887. The reversal of 81897874 is 47879818.

It can be written as a sum of positive squares in 2 ways, for example, as 81812025 + 85849 = 9045^2 + 293^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1204347 + ... + 1204414.

Almost surely, 2^81897874 is an apocalyptic number.

81897874 is a deficient number, since it is larger than the sum of its proper divisors (48175274).

81897874 is a wasteful number, since it uses less digits than its factorization.

81897874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2408780.

The product of its digits is 903168, while the sum is 52.

The square root of 81897874 is about 9049.7444162805. The cubic root of 81897874 is about 434.2677140900.

The spelling of 81897874 in words is "eighty-one million, eight hundred ninety-seven thousand, eight hundred seventy-four".