81579894554 has 8 divisors (see below), whose sum is σ = 122374854228. Its totient is φ = 40788276480.

The previous prime is 81579894553. The next prime is 81579894601. The reversal of 81579894554 is 45549897518.

It can be written as a sum of positive squares in 2 ways, for example, as 78868297225 + 2711597329 = 280835^2 + 52073^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81579894553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 773447 + ... + 872570.

Almost surely, 2^81579894554 is an apocalyptic number.

81579894554 is a deficient number, since it is larger than the sum of its proper divisors (40794959674).

81579894554 is a wasteful number, since it uses less digits than its factorization.

81579894554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1670800.

The product of its digits is 72576000, while the sum is 65.

The spelling of 81579894554 in words is "eighty-one billion, five hundred seventy-nine million, eight hundred ninety-four thousand, five hundred fifty-four".