81321077 has 4 divisors (see below), whose sum is σ = 84856800. Its totient is φ = 77785356.

The previous prime is 81321043. The next prime is 81321089. The reversal of 81321077 is 77012318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81321077 - 2¹⁰ = 81320053 is a prime.

It is a super-2 number, since 2×81321077² = 13226235128879858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81321377) 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, 1767827 + ... + 1767872.

It is an arithmetic number, because the mean of its divisors is an integer number (21214200).

Almost surely, 2^81321077 is an apocalyptic number.

It is an amenable number.

81321077 is a deficient number, since it is larger than the sum of its proper divisors (3535723).

81321077 is a wasteful number, since it uses less digits than its factorization.

81321077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3535722.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 81321077 is about 9017.8199693718. The cubic root of 81321077 is about 433.2458126336.

The spelling of 81321077 in words is "eighty-one million, three hundred twenty-one thousand, seventy-seven".