81847479 has 8 divisors (see below), whose sum is σ = 124720000. Its totient is φ = 46769976.

The previous prime is 81847463. The next prime is 81847481. The reversal of 81847479 is 97474818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81847479 - 2⁴ = 81847463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81847429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1948729 + ... + 1948770.

It is an arithmetic number, because the mean of its divisors is an integer number (15590000).

Almost surely, 2^81847479 is an apocalyptic number.

81847479 is a deficient number, since it is larger than the sum of its proper divisors (42872521).

81847479 is a wasteful number, since it uses less digits than its factorization.

81847479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3897509.

The product of its digits is 451584, while the sum is 48.

The square root of 81847479 is about 9046.9596550443. The cubic root of 81847479 is about 434.1786217818.

The spelling of 81847479 in words is "eighty-one million, eight hundred forty-seven thousand, four hundred seventy-nine".