81806455 has 8 divisors (see below), whose sum is σ = 98216352. Its totient is φ = 65412768.

The previous prime is 81806447. The next prime is 81806467. The reversal of 81806455 is 55460818.

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

It is a cyclic number.

It is not a de Polignac number, because 81806455 - 2³ = 81806447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17109 + ... + 21361.

It is an arithmetic number, because the mean of its divisors is an integer number (12277044).

Almost surely, 2^81806455 is an apocalyptic number.

81806455 is a deficient number, since it is larger than the sum of its proper divisors (16409897).

81806455 is a wasteful number, since it uses less digits than its factorization.

81806455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8105.

The product of its (nonzero) digits is 38400, while the sum is 37.

The square root of 81806455 is about 9044.6920898392. The cubic root of 81806455 is about 434.1060692703.

The spelling of 81806455 in words is "eighty-one million, eight hundred six thousand, four hundred fifty-five".