81324780 has 96 divisors (see below), whose sum is σ = 245403648. Its totient is φ = 20064000.

The previous prime is 81324767. The next prime is 81324809. The reversal of 81324780 is 8742318.

It is a super-2 number, since 2×81324780² = 13227439684096800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41830 + ... + 43730.

It is an arithmetic number, because the mean of its divisors is an integer number (2556288).

Almost surely, 2^81324780 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 81324780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122701824).

81324780 is an abundant number, since it is smaller than the sum of its proper divisors (164078868).

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

81324780 is a wasteful number, since it uses less digits than its factorization.

81324780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1967 (or 1965 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 81324780 is about 9018.0252827324. The cubic root of 81324780 is about 433.2523885626.

The spelling of 81324780 in words is "eighty-one million, three hundred twenty-four thousand, seven hundred eighty".