81510222 has 32 divisors (see below), whose sum is σ = 168791040. Its totient is φ = 26213760.

The previous prime is 81510203. The next prime is 81510227. The reversal of 81510222 is 22201518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81510227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109929 + ... + 110667.

It is an arithmetic number, because the mean of its divisors is an integer number (5274720).

Almost surely, 2^81510222 is an apocalyptic number.

81510222 is an abundant number, since it is smaller than the sum of its proper divisors (87280818).

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

81510222 is a wasteful number, since it uses less digits than its factorization.

81510222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 81510222 is about 9028.3011691015. The cubic root of 81510222 is about 433.5814485727.

The spelling of 81510222 in words is "eighty-one million, five hundred ten thousand, two hundred twenty-two".