81660814 has 4 divisors (see below), whose sum is σ = 122491224. Its totient is φ = 40830406.

The previous prime is 81660811. The next prime is 81660853. The reversal of 81660814 is 41806618.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81660814.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81660811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20415202 + ... + 20415205.

It is an arithmetic number, because the mean of its divisors is an integer number (30622806).

Almost surely, 2^81660814 is an apocalyptic number.

81660814 is a deficient number, since it is larger than the sum of its proper divisors (40830410).

81660814 is a wasteful number, since it uses less digits than its factorization.

81660814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40830409.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81660814 is about 9036.6373170555. The cubic root of 81660814 is about 433.8483015165.

The spelling of 81660814 in words is "eighty-one million, six hundred sixty thousand, eight hundred fourteen".