81534566 has 8 divisors (see below), whose sum is σ = 124904160. Its totient is φ = 39899848.

The previous prime is 81534553. The next prime is 81534641. The reversal of 81534566 is 66543518.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 433601 + ... + 433788.

It is an arithmetic number, because the mean of its divisors is an integer number (15613020).

Almost surely, 2^81534566 is an apocalyptic number.

81534566 is a deficient number, since it is larger than the sum of its proper divisors (43369594).

81534566 is a wasteful number, since it uses less digits than its factorization.

81534566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 867438.

The product of its digits is 86400, while the sum is 38.

The square root of 81534566 is about 9029.6492733660. The cubic root of 81534566 is about 433.6246090332.

The spelling of 81534566 in words is "eighty-one million, five hundred thirty-four thousand, five hundred sixty-six".