81969180 has 48 divisors (see below), whose sum is σ = 234858624. Its totient is φ = 21349440.

The previous prime is 81969163. The next prime is 81969187. The reversal of 81969180 is 8196918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81969187) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13306 + ... + 18465.

It is an arithmetic number, because the mean of its divisors is an integer number (4892888).

Almost surely, 2^81969180 is an apocalyptic number.

It is an amenable number.

81969180 is an abundant number, since it is smaller than the sum of its proper divisors (152889444).

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

81969180 is a wasteful number, since it uses less digits than its factorization.

81969180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31826 (or 31824 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 81969180 is about 9053.6832283883. The cubic root of 81969180 is about 434.3937121142.

The spelling of 81969180 in words is "eighty-one million, nine hundred sixty-nine thousand, one hundred eighty".