220913821 has 2 divisors, whose sum is σ = 220913822. Its totient is φ = 220913820.

The previous prime is 220913809. The next prime is 220913831. The reversal of 220913821 is 128319022.

220913821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125753796 + 95160025 = 11214^2 + 9755^2 .

It is a cyclic number.

It is not a de Polignac number, because 220913821 - 2⁵ = 220913789 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 220913821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220913831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110456910 + 110456911.

It is an arithmetic number, because the mean of its divisors is an integer number (110456911).

Almost surely, 2^220913821 is an apocalyptic number.

It is an amenable number.

220913821 is a deficient number, since it is larger than the sum of its proper divisors (1).

220913821 is an equidigital number, since it uses as much as digits as its factorization.

220913821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 220913821 is about 14863.1699512587. The cubic root of 220913821 is about 604.5157621482.

The spelling of 220913821 in words is "two hundred twenty million, nine hundred thirteen thousand, eight hundred twenty-one".