81556423 has 8 divisors (see below), whose sum is σ = 89873168. Its totient is φ = 73531584.

The previous prime is 81556411. The next prime is 81556441. The reversal of 81556423 is 32465518.

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

It is a cyclic number.

It is not a de Polignac number, because 81556423 - 2²⁵ = 48001991 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 (81556483) 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, 72390 + ... + 73507.

It is an arithmetic number, because the mean of its divisors is an integer number (11234146).

Almost surely, 2^81556423 is an apocalyptic number.

81556423 is a deficient number, since it is larger than the sum of its proper divisors (8316745).

81556423 is a wasteful number, since it uses less digits than its factorization.

81556423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145953.

The product of its digits is 28800, while the sum is 34.

The square root of 81556423 is about 9030.8594829064. The cubic root of 81556423 is about 433.6633528722.

The spelling of 81556423 in words is "eighty-one million, five hundred fifty-six thousand, four hundred twenty-three".