81465216 has 64 divisors (see below), whose sum is σ = 247313280. Its totient is φ = 23275008.

The previous prime is 81465119. The next prime is 81465221. The reversal of 81465216 is 61256418.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12466 + ... + 17841.

It is an arithmetic number, because the mean of its divisors is an integer number (3864270).

Almost surely, 2^81465216 is an apocalyptic number.

It is an amenable number.

81465216 is an abundant number, since it is smaller than the sum of its proper divisors (165848064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81465216 is a wasteful number, since it uses less digits than its factorization.

81465216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30331 (or 30319 counting only the distinct ones).

The product of its digits is 11520, while the sum is 33.

The square root of 81465216 is about 9025.8083294517. The cubic root of 81465216 is about 433.5016329830.

The spelling of 81465216 in words is "eighty-one million, four hundred sixty-five thousand, two hundred sixteen".