81052920 has 256 divisors, whose sum is σ = 304819200. Its totient is φ = 19008000.

The previous prime is 81052919. The next prime is 81052931. The reversal of 81052920 is 2925018.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 322795 + ... + 323045.

It is an arithmetic number, because the mean of its divisors is an integer number (1190700).

Almost surely, 2^81052920 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 81052920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152409600).

81052920 is an abundant number, since it is smaller than the sum of its proper divisors (223766280).

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

81052920 is a wasteful number, since it uses less digits than its factorization.

81052920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 81052920 is about 9002.9395199568. The cubic root of 81052920 is about 432.7690775511.

Adding to 81052920 its reverse (2925018), we get a palindrome (83977938).

It can be divided in two parts, 8105 and 2920, that added together give a square (11025 = 105²).

The spelling of 81052920 in words is "eighty-one million, fifty-two thousand, nine hundred twenty".