81215832 has 32 divisors (see below), whose sum is σ = 205490880. Its totient is φ = 26745120.

The previous prime is 81215831. The next prime is 81215837. The reversal of 81215832 is 23851218.

It is a super-2 number, since 2×81215832² = 13192022734904448, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81215832.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81215831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18394 + ... + 22377.

It is an arithmetic number, because the mean of its divisors is an integer number (6421590).

Almost surely, 2^81215832 is an apocalyptic number.

It is an amenable number.

81215832 is an abundant number, since it is smaller than the sum of its proper divisors (124275048).

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

81215832 is a wasteful number, since it uses less digits than its factorization.

81215832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40863 (or 40859 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 81215832 is about 9011.9826897304. The cubic root of 81215832 is about 433.0588310138.

The spelling of 81215832 in words is "eighty-one million, two hundred fifteen thousand, eight hundred thirty-two".