81927773 has 4 divisors (see below), whose sum is σ = 82009980. Its totient is φ = 81845568.

The previous prime is 81927767. The next prime is 81927787. The reversal of 81927773 is 37772918.

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

It can be written as a sum of positive squares in 2 ways, for example, as 37478884 + 44448889 = 6122^2 + 6667^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81927773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81927673) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39590 + ... + 41607.

It is an arithmetic number, because the mean of its divisors is an integer number (20502495).

Almost surely, 2^81927773 is an apocalyptic number.

It is an amenable number.

81927773 is a deficient number, since it is larger than the sum of its proper divisors (82207).

81927773 is a wasteful number, since it uses less digits than its factorization.

81927773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82206.

The product of its digits is 148176, while the sum is 44.

The square root of 81927773 is about 9051.3961906437. The cubic root of 81927773 is about 434.3205546583.

The spelling of 81927773 in words is "eighty-one million, nine hundred twenty-seven thousand, seven hundred seventy-three".