81355546 has 4 divisors (see below), whose sum is σ = 122033322. Its totient is φ = 40677772.

The previous prime is 81355541. The next prime is 81355607. The reversal of 81355546 is 64555318.

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., 74909025 + 6446521 = 8655^2 + 2539^2 .

It is not an unprimeable number, because it can be changed into a prime (81355541) by changing a digit.

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 as a sum of consecutive naturals, namely, 20338885 + ... + 20338888.

Almost surely, 2^81355546 is an apocalyptic number.

81355546 is a deficient number, since it is larger than the sum of its proper divisors (40677776).

81355546 is a wasteful number, since it uses less digits than its factorization.

81355546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40677775.

The product of its digits is 72000, while the sum is 37.

The square root of 81355546 is about 9019.7309272505. The cubic root of 81355546 is about 433.3070162847.

The spelling of 81355546 in words is "eighty-one million, three hundred fifty-five thousand, five hundred forty-six".