81577577 has 8 divisors (see below), whose sum is σ = 88483752. Its totient is φ = 74905600.

The previous prime is 81577567. The next prime is 81577597. The reversal of 81577577 is 77577518.

It can be written as a sum of positive squares in 4 ways, for example, as 6651241 + 74926336 = 2579^2 + 8656^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81577577 - 2⁶ = 81577513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81577567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57824 + ... + 59217.

It is an arithmetic number, because the mean of its divisors is an integer number (11060469).

Almost surely, 2^81577577 is an apocalyptic number.

It is an amenable number.

81577577 is a deficient number, since it is larger than the sum of its proper divisors (6906175).

81577577 is a wasteful number, since it uses less digits than its factorization.

81577577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117099.

The product of its digits is 480200, while the sum is 47.

The square root of 81577577 is about 9032.0306133228. The cubic root of 81577577 is about 433.7008439784.

The spelling of 81577577 in words is "eighty-one million, five hundred seventy-seven thousand, five hundred seventy-seven".