81555312 has 20 divisors (see below), whose sum is σ = 210684680. Its totient is φ = 27185088.

The previous prime is 81555311. The next prime is 81555317. The reversal of 81555312 is 21355518.

It is a self number, because there is not a number n which added to its sum of digits gives 81555312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81555311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 849487 + ... + 849582.

It is an arithmetic number, because the mean of its divisors is an integer number (10534234).

Almost surely, 2^81555312 is an apocalyptic number.

It is an amenable number.

81555312 is an abundant number, since it is smaller than the sum of its proper divisors (129129368).

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

81555312 is a wasteful number, since it uses less digits than its factorization.

81555312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1699080 (or 1699074 counting only the distinct ones).

The product of its digits is 6000, while the sum is 30.

The square root of 81555312 is about 9030.7979713866. The cubic root of 81555312 is about 433.6613836745.

The spelling of 81555312 in words is "eighty-one million, five hundred fifty-five thousand, three hundred twelve".