81774842 has 4 divisors (see below), whose sum is σ = 122662266. Its totient is φ = 40887420.

The previous prime is 81774829. The next prime is 81774929. The reversal of 81774842 is 24847718.

It is a happy number.

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., 76930441 + 4844401 = 8771^2 + 2201^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81774842.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20443709 + ... + 20443712.

Almost surely, 2^81774842 is an apocalyptic number.

81774842 is a deficient number, since it is larger than the sum of its proper divisors (40887424).

81774842 is a wasteful number, since it uses less digits than its factorization.

81774842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40887423.

The product of its digits is 100352, while the sum is 41.

The square root of 81774842 is about 9042.9443214033. The cubic root of 81774842 is about 434.0501439227.

The spelling of 81774842 in words is "eighty-one million, seven hundred seventy-four thousand, eight hundred forty-two".