81289655 has 4 divisors (see below), whose sum is σ = 97547592. Its totient is φ = 65031720.

The previous prime is 81289643. The next prime is 81289667. The reversal of 81289655 is 55698218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55698218 = 2 ⋅27849109.

It is an interprime number because it is at equal distance from previous prime (81289643) and next prime (81289667).

It is not a de Polignac number, because 81289655 - 2⁶ = 81289591 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 3 ways as a sum of consecutive naturals, for example, 8128961 + ... + 8128970.

It is an arithmetic number, because the mean of its divisors is an integer number (24386898).

Almost surely, 2^81289655 is an apocalyptic number.

81289655 is a deficient number, since it is larger than the sum of its proper divisors (16257937).

81289655 is a wasteful number, since it uses less digits than its factorization.

81289655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16257936.

The product of its digits is 172800, while the sum is 44.

The square root of 81289655 is about 9016.0775839608. The cubic root of 81289655 is about 433.1900042085.

The spelling of 81289655 in words is "eighty-one million, two hundred eighty-nine thousand, six hundred fifty-five".