81388252 has 12 divisors (see below), whose sum is σ = 155377656. Its totient is φ = 36994640.

The previous prime is 81388247. The next prime is 81388259. The reversal of 81388252 is 25288318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81388259) 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, 924823 + ... + 924910.

It is an arithmetic number, because the mean of its divisors is an integer number (12948138).

Almost surely, 2^81388252 is an apocalyptic number.

It is an amenable number.

81388252 is a deficient number, since it is larger than the sum of its proper divisors (73989404).

81388252 is a wasteful number, since it uses less digits than its factorization.

81388252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1849748 (or 1849746 counting only the distinct ones).

The product of its digits is 30720, while the sum is 37.

The square root of 81388252 is about 9021.5437703311. The cubic root of 81388252 is about 433.3650735462.

The spelling of 81388252 in words is "eighty-one million, three hundred eighty-eight thousand, two hundred fifty-two".