81777081 has 8 divisors (see below), whose sum is σ = 109832544. Its totient is φ = 54119840.

The previous prime is 81777079. The next prime is 81777103. The reversal of 81777081 is 18077718.

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 81777081 - 2¹ = 81777079 is a prime.

It is a super-2 number, since 2×81777081² = 13374981953761122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81777041) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 99075 + ... + 99896.

It is an arithmetic number, because the mean of its divisors is an integer number (13729068).

Almost surely, 2^81777081 is an apocalyptic number.

It is an amenable number.

81777081 is a deficient number, since it is larger than the sum of its proper divisors (28055463).

81777081 is a wasteful number, since it uses less digits than its factorization.

81777081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199111.

The product of its (nonzero) digits is 21952, while the sum is 39.

The square root of 81777081 is about 9043.0681187305. The cubic root of 81777081 is about 434.0541053261.

The spelling of 81777081 in words is "eighty-one million, seven hundred seventy-seven thousand, eighty-one".