821274666 has 8 divisors (see below), whose sum is σ = 1642549344. Its totient is φ = 273758220.

The previous prime is 821274613. The next prime is 821274721. The reversal of 821274666 is 666472128.

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

821274666 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 68439550 + ... + 68439561.

It is an arithmetic number, because the mean of its divisors is an integer number (205318668).

Almost surely, 2^821274666 is an apocalyptic number.

821274666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

821274666 is a wasteful number, since it uses less digits than its factorization.

821274666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136879116.

The product of its digits is 193536, while the sum is 42.

The square root of 821274666 is about 28657.8901177320. The cubic root of 821274666 is about 936.4749010009.

The spelling of 821274666 in words is "eight hundred twenty-one million, two hundred seventy-four thousand, six hundred sixty-six".