81183420 has 72 divisors (see below), whose sum is σ = 254217600. Its totient is φ = 20949120.

The previous prime is 81183419. The next prime is 81183461. The reversal of 81183420 is 2438118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1695 + ... + 12854.

It is an arithmetic number, because the mean of its divisors is an integer number (3530800).

Almost surely, 2^81183420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81183420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127108800).

81183420 is an abundant number, since it is smaller than the sum of its proper divisors (173034180).

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

81183420 is a wasteful number, since it uses less digits than its factorization.

81183420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14595 (or 14590 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81183420 is about 9010.1842378500. The cubic root of 81183420 is about 433.0012142901.

The spelling of 81183420 in words is "eighty-one million, one hundred eighty-three thousand, four hundred twenty".