81355380 has 24 divisors (see below), whose sum is σ = 227795232. Its totient is φ = 21694752.

The previous prime is 81355363. The next prime is 81355381. The reversal of 81355380 is 8355318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81355381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 677902 + ... + 678021.

It is an arithmetic number, because the mean of its divisors is an integer number (9491468).

Almost surely, 2^81355380 is an apocalyptic number.

It is an amenable number.

81355380 is an abundant number, since it is smaller than the sum of its proper divisors (146439852).

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

81355380 is a wasteful number, since it uses less digits than its factorization.

81355380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1355935 (or 1355933 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 81355380 is about 9019.7217251975. The cubic root of 81355380 is about 433.3067215742.

The spelling of 81355380 in words is "eighty-one million, three hundred fifty-five thousand, three hundred eighty".