821493394 has 8 divisors (see below), whose sum is σ = 1240089228. Its totient is φ = 408130320.

The previous prime is 821493383. The next prime is 821493419. The reversal of 821493394 is 493394128.

It can be written as a sum of positive squares in 2 ways, for example, as 819963225 + 1530169 = 28635^2 + 1237^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 821493394.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1307797 + ... + 1308424.

Almost surely, 2^821493394 is an apocalyptic number.

821493394 is a deficient number, since it is larger than the sum of its proper divisors (418595834).

821493394 is a wasteful number, since it uses less digits than its factorization.

821493394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2616380.

The product of its digits is 186624, while the sum is 43.

The square root of 821493394 is about 28661.7060552927. The cubic root of 821493394 is about 936.5580299504.

The spelling of 821493394 in words is "eight hundred twenty-one million, four hundred ninety-three thousand, three hundred ninety-four".