821217312 has 48 divisors (see below), whose sum is σ = 2395219680. Its totient is φ = 273738816.

The previous prime is 821217307. The next prime is 821217343. The reversal of 821217312 is 213712128.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 474378 + ... + 476105.

It is an arithmetic number, because the mean of its divisors is an integer number (49900410).

Almost surely, 2^821217312 is an apocalyptic number.

It is an amenable number.

821217312 is an abundant number, since it is smaller than the sum of its proper divisors (1574002368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821217312 is a wasteful number, since it uses less digits than its factorization.

821217312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950502 (or 950488 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 821217312 is about 28656.8894334329. The cubic root of 821217312 is about 936.4531008107.

The spelling of 821217312 in words is "eight hundred twenty-one million, two hundred seventeen thousand, three hundred twelve".