81172242 has 24 divisors (see below), whose sum is σ = 178500816. Its totient is φ = 26653176.

The previous prime is 81172211. The next prime is 81172271. The reversal of 81172242 is 24227118.

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 11 ways as a sum of consecutive naturals, for example, 32448 + ... + 34859.

It is an arithmetic number, because the mean of its divisors is an integer number (7437534).

Almost surely, 2^81172242 is an apocalyptic number.

81172242 is an abundant number, since it is smaller than the sum of its proper divisors (97328574).

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

81172242 is a wasteful number, since it uses less digits than its factorization.

81172242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67382 (or 67379 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 81172242 is about 9009.5639184147. The cubic root of 81172242 is about 432.9813403235.

The spelling of 81172242 in words is "eighty-one million, one hundred seventy-two thousand, two hundred forty-two".