821557367449 has 16 divisors (see below), whose sum is σ = 1024998873472. Its totient is φ = 641118976128.

The previous prime is 821557367381. The next prime is 821557367459. The reversal of 821557367449 is 944763755128.

It is a cyclic number.

It is not a de Polignac number, because 821557367449 - 2⁷ = 821557367321 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821557367459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61829679 + ... + 61842964.

It is an arithmetic number, because the mean of its divisors is an integer number (64062429592).

Almost surely, 2^821557367449 is an apocalyptic number.

It is an amenable number.

821557367449 is a deficient number, since it is larger than the sum of its proper divisors (203441506023).

821557367449 is a wasteful number, since it uses less digits than its factorization.

821557367449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123672736.

The product of its digits is 50803200, while the sum is 61.

The spelling of 821557367449 in words is "eight hundred twenty-one billion, five hundred fifty-seven million, three hundred sixty-seven thousand, four hundred forty-nine".