81872460 has 36 divisors (see below), whose sum is σ = 248347008. Its totient is φ = 21832608.

The previous prime is 81872447. The next prime is 81872467. The reversal of 81872460 is 6427818.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (81872467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 227244 + ... + 227603.

It is an arithmetic number, because the mean of its divisors is an integer number (6898528).

Almost surely, 2^81872460 is an apocalyptic number.

It is an amenable number.

81872460 is an abundant number, since it is smaller than the sum of its proper divisors (166474548).

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

81872460 is a wasteful number, since it uses less digits than its factorization.

81872460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454862 (or 454857 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 81872460 is about 9048.3401792815. The cubic root of 81872460 is about 434.2227897595. Note that the first 3 decimals are identical.

The spelling of 81872460 in words is "eighty-one million, eight hundred seventy-two thousand, four hundred sixty".