81636290 has 8 divisors (see below), whose sum is σ = 146945340. Its totient is φ = 32654512.

The previous prime is 81636283. The next prime is 81636337. The reversal of 81636290 is 9263618.

It can be written as a sum of positive squares in 2 ways, for example, as 71757841 + 9878449 = 8471^2 + 3143^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 81636290.

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, 4081805 + ... + 4081824.

Almost surely, 2^81636290 is an apocalyptic number.

81636290 is a deficient number, since it is larger than the sum of its proper divisors (65309050).

81636290 is a wasteful number, since it uses less digits than its factorization.

81636290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8163636.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 81636290 is about 9035.2802944900. The cubic root of 81636290 is about 433.8048667261.

The spelling of 81636290 in words is "eighty-one million, six hundred thirty-six thousand, two hundred ninety".