81187522 has 8 divisors (see below), whose sum is σ = 131149116. Its totient is φ = 37471152.

The previous prime is 81187517. The next prime is 81187531. The reversal of 81187522 is 22578118.

It can be written as a sum of positive squares in 2 ways, for example, as 63218401 + 17969121 = 7951^2 + 4239^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 1561273 + ... + 1561324.

Almost surely, 2^81187522 is an apocalyptic number.

81187522 is a deficient number, since it is larger than the sum of its proper divisors (49961594).

81187522 is a wasteful number, since it uses less digits than its factorization.

81187522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3122612.

The product of its digits is 8960, while the sum is 34.

The square root of 81187522 is about 9010.4118662800. The cubic root of 81187522 is about 433.0085069986.

The spelling of 81187522 in words is "eighty-one million, one hundred eighty-seven thousand, five hundred twenty-two".