81479120 has 20 divisors (see below), whose sum is σ = 189439140. Its totient is φ = 32591616.

The previous prime is 81479119. The next prime is 81479149. The reversal of 81479120 is 2197418.

It can be written as a sum of positive squares in 2 ways, for example, as 58859584 + 22619536 = 7672^2 + 4756^2 .

It is a tau number, because it is divible by the number of its divisors (20).

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 3 ways as a sum of consecutive naturals, for example, 509165 + ... + 509324.

It is an arithmetic number, because the mean of its divisors is an integer number (9471957).

Almost surely, 2^81479120 is an apocalyptic number.

81479120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81479120 is an abundant number, since it is smaller than the sum of its proper divisors (107960020).

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

81479120 is a wasteful number, since it uses less digits than its factorization.

81479120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018502 (or 1018496 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 81479120 is about 9026.5785323122. The cubic root of 81479120 is about 433.5262940761.

The spelling of 81479120 in words is "eighty-one million, four hundred seventy-nine thousand, one hundred twenty".