821094977 has 4 divisors (see below), whose sum is σ = 821152980. Its totient is φ = 821036976.

The previous prime is 821094973. The next prime is 821094979. The reversal of 821094977 is 779490128.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 107350321 + 713744656 = 10361^2 + 26716^2 .

It is a cyclic number.

It is not a de Polignac number, because 821094977 - 2² = 821094973 is a prime.

It is a super-2 number, since 2×821094977² = 1348393922509261058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821094973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7799 + ... + 41267.

It is an arithmetic number, because the mean of its divisors is an integer number (205288245).

Almost surely, 2^821094977 is an apocalyptic number.

It is an amenable number.

821094977 is a deficient number, since it is larger than the sum of its proper divisors (58003).

821094977 is a wasteful number, since it uses less digits than its factorization.

821094977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58002.

The product of its (nonzero) digits is 254016, while the sum is 47.

The square root of 821094977 is about 28654.7548759364. The cubic root of 821094977 is about 936.4065980245.

The spelling of 821094977 in words is "eight hundred twenty-one million, ninety-four thousand, nine hundred seventy-seven".