81057077 has 4 divisors (see below), whose sum is σ = 81117996. Its totient is φ = 80996160.

The previous prime is 81057073. The next prime is 81057103. The reversal of 81057077 is 77075018.

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 15673681 + 65383396 = 3959^2 + 8086^2 .

It is a cyclic number.

It is not a de Polignac number, because 81057077 - 2² = 81057073 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 (81057073) 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, 28418 + ... + 31139.

It is an arithmetic number, because the mean of its divisors is an integer number (20279499).

Almost surely, 2^81057077 is an apocalyptic number.

It is an amenable number.

81057077 is a deficient number, since it is larger than the sum of its proper divisors (60919).

81057077 is a wasteful number, since it uses less digits than its factorization.

81057077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60918.

The product of its (nonzero) digits is 13720, while the sum is 35.

The square root of 81057077 is about 9003.1703860362. The cubic root of 81057077 is about 432.7764759697.

The spelling of 81057077 in words is "eighty-one million, fifty-seven thousand, seventy-seven".