821264390 has 16 divisors (see below), whose sum is σ = 1565233632. Its totient is φ = 309181824.

The previous prime is 821264383. The next prime is 821264413. The reversal of 821264390 is 93462128.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 821264390.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2415314 + ... + 2415653.

It is an arithmetic number, because the mean of its divisors is an integer number (97827102).

Almost surely, 2^821264390 is an apocalyptic number.

821264390 is a deficient number, since it is larger than the sum of its proper divisors (743969242).

821264390 is a wasteful number, since it uses less digits than its factorization.

821264390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4830991.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 821264390 is about 28657.7108297226. The cubic root of 821264390 is about 936.4709951797.

The spelling of 821264390 in words is "eight hundred twenty-one million, two hundred sixty-four thousand, three hundred ninety".