821315649 has 32 divisors (see below), whose sum is σ = 1398620160. Its totient is φ = 416246400.

The previous prime is 821315633. The next prime is 821315657. The reversal of 821315649 is 946513128.

It is not a de Polignac number, because 821315649 - 2⁴ = 821315633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821315669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33889 + ... + 52830.

It is an arithmetic number, because the mean of its divisors is an integer number (43706880).

Almost surely, 2^821315649 is an apocalyptic number.

It is an amenable number.

821315649 is a deficient number, since it is larger than the sum of its proper divisors (577304511).

821315649 is a wasteful number, since it uses less digits than its factorization.

821315649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86781.

The product of its digits is 51840, while the sum is 39.

The square root of 821315649 is about 28658.6051474945. The cubic root of 821315649 is about 936.4904779709.

The spelling of 821315649 in words is "eight hundred twenty-one million, three hundred fifteen thousand, six hundred forty-nine".