81635190 has 128 divisors (see below), whose sum is σ = 255467520. Its totient is φ = 16201728.

The previous prime is 81635167. The next prime is 81635221. The reversal of 81635190 is 9153618.

It is a super-2 number, since 2×81635190² = 13328608492672200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 45531 + ... + 47289.

It is an arithmetic number, because the mean of its divisors is an integer number (1995840).

Almost surely, 2^81635190 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81635190, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127733760).

81635190 is an abundant number, since it is smaller than the sum of its proper divisors (173832330).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81635190 is a wasteful number, since it uses less digits than its factorization.

81635190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1806.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 81635190 is about 9035.2194217960. The cubic root of 81635190 is about 433.8029182973.

The spelling of 81635190 in words is "eighty-one million, six hundred thirty-five thousand, one hundred ninety".