81599522 has 4 divisors (see below), whose sum is σ = 122399286. Its totient is φ = 40799760.

The previous prime is 81599521. The next prime is 81599527. The reversal of 81599522 is 22599518.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 76755121 + 4844401 = 8761^2 + 2201^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81599522.

It is not an unprimeable number, because it can be changed into a prime (81599521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20399879 + ... + 20399882.

Almost surely, 2^81599522 is an apocalyptic number.

81599522 is a deficient number, since it is larger than the sum of its proper divisors (40799764).

81599522 is a wasteful number, since it uses less digits than its factorization.

81599522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40799763.

The product of its digits is 64800, while the sum is 41.

The square root of 81599522 is about 9033.2453747255. The cubic root of 81599522 is about 433.7397301203.

The spelling of 81599522 in words is "eighty-one million, five hundred ninety-nine thousand, five hundred twenty-two".