81595090 has 16 divisors (see below), whose sum is σ = 149643288. Its totient is φ = 32022016.

The previous prime is 81595061. The next prime is 81595103. The reversal of 81595090 is 9059518.

It is a Cunningham number, because it is equal to 9033²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 81595089 + 1 = 9033^2 + 1^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76447 + ... + 77506.

Almost surely, 2^81595090 is an apocalyptic number.

81595090 is a deficient number, since it is larger than the sum of its proper divisors (68048198).

81595090 is a wasteful number, since it uses less digits than its factorization.

81595090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154013.

The product of its (nonzero) digits is 16200, while the sum is 37.

The square root of 81595090 is about 9033.0000553526. Note that the first 4 decimals coincide. The cubic root of 81595090 is about 433.7318772586.

The spelling of 81595090 in words is "eighty-one million, five hundred ninety-five thousand, ninety".