81015120 has 80 divisors (see below), whose sum is σ = 279059520. Its totient is φ = 21603456.

The previous prime is 81015119. The next prime is 81015161. The reversal of 81015120 is 2151018.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×81015120² = 13126899337228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 81015093 and 81015102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16594 + ... + 20913.

It is an arithmetic number, because the mean of its divisors is an integer number (3488244).

Almost surely, 2^81015120 is an apocalyptic number.

81015120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81015120 is an abundant number, since it is smaller than the sum of its proper divisors (198044400).

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

81015120 is a wasteful number, since it uses less digits than its factorization.

81015120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37529 (or 37517 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The square root of 81015120 is about 9000.8399608037. The cubic root of 81015120 is about 432.7017914092.

Adding to 81015120 its reverse (2151018), we get a palindrome (83166138).

The spelling of 81015120 in words is "eighty-one million, fifteen thousand, one hundred twenty".