81410566 has 4 divisors (see below), whose sum is σ = 122115852. Its totient is φ = 40705282.

The previous prime is 81410531. The next prime is 81410587. The reversal of 81410566 is 66501418.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20352640 + ... + 20352643.

It is an arithmetic number, because the mean of its divisors is an integer number (30528963).

Almost surely, 2^81410566 is an apocalyptic number.

81410566 is a deficient number, since it is larger than the sum of its proper divisors (40705286).

81410566 is a wasteful number, since it uses less digits than its factorization.

81410566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40705285.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 81410566 is about 9022.7803918748. The cubic root of 81410566 is about 433.4046747761.

The spelling of 81410566 in words is "eighty-one million, four hundred ten thousand, five hundred sixty-six".