81939060 has 192 divisors, whose sum is σ = 297561600. Its totient is φ = 18330624.

The previous prime is 81939049. The next prime is 81939061. The reversal of 81939060 is 6093918.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81939061) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 200136 + ... + 200544.

It is an arithmetic number, because the mean of its divisors is an integer number (1549800).

Almost surely, 2^81939060 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 81939060, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148780800).

81939060 is an abundant number, since it is smaller than the sum of its proper divisors (215622540).

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

81939060 is a wasteful number, since it uses less digits than its factorization.

81939060 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 81939060 is about 9052.0196641413. The cubic root of 81939060 is about 434.3404988556.

The spelling of 81939060 in words is "eighty-one million, nine hundred thirty-nine thousand, sixty".