81478020 has 48 divisors (see below), whose sum is σ = 245689920. Its totient is φ = 20055936.

The previous prime is 81478009. The next prime is 81478031. The reversal of 81478020 is 2087418.

It is an interprime number because it is at equal distance from previous prime (81478009) and next prime (81478031).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 51450 + ... + 53009.

It is an arithmetic number, because the mean of its divisors is an integer number (5118540).

Almost surely, 2^81478020 is an apocalyptic number.

It is an amenable number.

81478020 is an abundant number, since it is smaller than the sum of its proper divisors (164211900).

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

81478020 is a wasteful number, since it uses less digits than its factorization.

81478020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104484 (or 104482 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 81478020 is about 9026.5176009356. The cubic root of 81478020 is about 433.5243431425.

The spelling of 81478020 in words is "eighty-one million, four hundred seventy-eight thousand, twenty".