1221806823 has 8 divisors (see below), whose sum is σ = 1629415536. Its totient is φ = 814368000.

The previous prime is 1221806819. The next prime is 1221806849. The reversal of 1221806823 is 3286081221.

1221806823 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 1221806823 - 2² = 1221806819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221806123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24618 + ... + 55223.

It is an arithmetic number, because the mean of its divisors is an integer number (203676942).

Almost surely, 2^1221806823 is an apocalyptic number.

1221806823 is a deficient number, since it is larger than the sum of its proper divisors (407608713).

1221806823 is an equidigital number, since it uses as much as digits as its factorization.

1221806823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84945.

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 1221806823 is about 34954.3534198532. The cubic root of 1221806823 is about 1069.0569683401.

The spelling of 1221806823 in words is "one billion, two hundred twenty-one million, eight hundred six thousand, eight hundred twenty-three".