81492538 has 4 divisors (see below), whose sum is σ = 122238810. Its totient is φ = 40746268.

The previous prime is 81492527. The next prime is 81492559. The reversal of 81492538 is 83529418.

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., 79512889 + 1979649 = 8917^2 + 1407^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 81492538.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20373133 + ... + 20373136.

Almost surely, 2^81492538 is an apocalyptic number.

81492538 is a deficient number, since it is larger than the sum of its proper divisors (40746272).

81492538 is a wasteful number, since it uses less digits than its factorization.

81492538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40746271.

The product of its digits is 69120, while the sum is 40.

The square root of 81492538 is about 9027.3217512172. The cubic root of 81492538 is about 433.5500905061.

The spelling of 81492538 in words is "eighty-one million, four hundred ninety-two thousand, five hundred thirty-eight".