81102905 has 8 divisors (see below), whose sum is σ = 104809992. Its totient is φ = 59891328.

The previous prime is 81102893. The next prime is 81102911. The reversal of 81102905 is 50920118.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4032064 + 77070841 = 2008^2 + 8779^2 .

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 81102905 - 2⁶ = 81102841 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, 623804 + ... + 623933.

It is an arithmetic number, because the mean of its divisors is an integer number (13101249).

Almost surely, 2^81102905 is an apocalyptic number.

It is an amenable number.

81102905 is a deficient number, since it is larger than the sum of its proper divisors (23707087).

81102905 is a wasteful number, since it uses less digits than its factorization.

81102905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247755.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 81102905 is about 9005.7151298495. The cubic root of 81102905 is about 432.8580215689.

The spelling of 81102905 in words is "eighty-one million, one hundred two thousand, nine hundred five".