81855554 has 8 divisors (see below), whose sum is σ = 133945488. Its totient is φ = 37207060.

The previous prime is 81855547. The next prime is 81855559. The reversal of 81855554 is 45555818.

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 (81855559) 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, 1860332 + ... + 1860375.

It is an arithmetic number, because the mean of its divisors is an integer number (16743186).

Almost surely, 2^81855554 is an apocalyptic number.

81855554 is a deficient number, since it is larger than the sum of its proper divisors (52089934).

81855554 is a wasteful number, since it uses less digits than its factorization.

81855554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3720720.

The product of its digits is 160000, while the sum is 41.

The square root of 81855554 is about 9047.4059265626. The cubic root of 81855554 is about 434.1928998721.

The spelling of 81855554 in words is "eighty-one million, eight hundred fifty-five thousand, five hundred fifty-four".