81510206 has 16 divisors (see below), whose sum is σ = 135087264. Its totient is φ = 36689664.

The previous prime is 81510203. The next prime is 81510227. The reversal of 81510206 is 60201518.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81510203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51335 + ... + 52898.

It is an arithmetic number, because the mean of its divisors is an integer number (8442954).

Almost surely, 2^81510206 is an apocalyptic number.

81510206 is a deficient number, since it is larger than the sum of its proper divisors (53577058).

81510206 is a wasteful number, since it uses less digits than its factorization.

81510206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104275.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 81510206 is about 9028.3002829990. The cubic root of 81510206 is about 433.5814202028.

The spelling of 81510206 in words is "eighty-one million, five hundred ten thousand, two hundred six".