81090105386 has 4 divisors (see below), whose sum is σ = 121635158082. Its totient is φ = 40545052692.

The previous prime is 81090105307. The next prime is 81090105391. The reversal of 81090105386 is 68350109018.

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

It can be written as a sum of positive squares in only one way, i.e., 41117700625 + 39972404761 = 202775^2 + 199931^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20272526345 + ... + 20272526348.

Almost surely, 2^81090105386 is an apocalyptic number.

81090105386 is a deficient number, since it is larger than the sum of its proper divisors (40545052696).

81090105386 is a wasteful number, since it uses less digits than its factorization.

81090105386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40545052695.

The product of its (nonzero) digits is 51840, while the sum is 41.

The spelling of 81090105386 in words is "eighty-one billion, ninety million, one hundred five thousand, three hundred eighty-six".