81077905 has 8 divisors (see below), whose sum is σ = 97458984. Its totient is φ = 64752000.

The previous prime is 81077897. The next prime is 81077917. The reversal of 81077905 is 50977018.

It can be written as a sum of positive squares in 4 ways, for example, as 6411024 + 74666881 = 2532^2 + 8641^2 .

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

It is not a de Polignac number, because 81077905 - 2³ = 81077897 is a prime.

It is a Duffinian 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, 10486 + ... + 16495.

It is an arithmetic number, because the mean of its divisors is an integer number (12182373).

Almost surely, 2^81077905 is an apocalyptic number.

It is an amenable number.

81077905 is a deficient number, since it is larger than the sum of its proper divisors (16381079).

81077905 is a wasteful number, since it uses less digits than its factorization.

81077905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27587.

The product of its (nonzero) digits is 17640, while the sum is 37.

The square root of 81077905 is about 9004.3270153854. The cubic root of 81077905 is about 432.8135407839.

The spelling of 81077905 in words is "eighty-one million, seventy-seven thousand, nine hundred five".