81571854 has 32 divisors (see below), whose sum is σ = 200793600. Its totient is φ = 21513312.

The previous prime is 81571843. The next prime is 81571873. The reversal of 81571854 is 45817518.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74154 + ... + 75245.

It is an arithmetic number, because the mean of its divisors is an integer number (6274800).

Almost surely, 2^81571854 is an apocalyptic number.

81571854 is an abundant number, since it is smaller than the sum of its proper divisors (119221746).

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

81571854 is a wasteful number, since it uses less digits than its factorization.

81571854 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149424.

The product of its digits is 44800, while the sum is 39.

The square root of 81571854 is about 9031.7137908594. The cubic root of 81571854 is about 433.6907017797.

It can be divided in two parts, 8157 and 1854, that added together give a triangular number (10011 = T₁₄₁).

The spelling of 81571854 in words is "eighty-one million, five hundred seventy-one thousand, eight hundred fifty-four".