81897365 has 32 divisors (see below), whose sum is σ = 113156352. Its totient is φ = 56320000.

The previous prime is 81897289. The next prime is 81897371. The reversal of 81897365 is 56379818.

It is a happy number.

It is not a de Polignac number, because 81897365 - 2¹⁰ = 81896341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 127445 + ... + 128085.

It is an arithmetic number, because the mean of its divisors is an integer number (3536136).

Almost surely, 2^81897365 is an apocalyptic number.

It is an amenable number.

81897365 is a deficient number, since it is larger than the sum of its proper divisors (31258987).

81897365 is a wasteful number, since it uses less digits than its factorization.

81897365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781.

The product of its digits is 362880, while the sum is 47.

The square root of 81897365 is about 9049.7162938956. The cubic root of 81897365 is about 434.2668144218.

The spelling of 81897365 in words is "eighty-one million, eight hundred ninety-seven thousand, three hundred sixty-five".