220001921 has 2 divisors, whose sum is σ = 220001922. Its totient is φ = 220001920.

The previous prime is 220001897. The next prime is 220001933. The reversal of 220001921 is 129100022.

220001921 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., 166126321 + 53875600 = 12889^2 + 7340^2 .

It is a cyclic number.

It is not a de Polignac number, because 220001921 - 2⁶ = 220001857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 220001921.

It is not a weakly prime, because it can be changed into another prime (220001321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110000960 + 110000961.

It is an arithmetic number, because the mean of its divisors is an integer number (110000961).

Almost surely, 2^220001921 is an apocalyptic number.

It is an amenable number.

220001921 is a deficient number, since it is larger than the sum of its proper divisors (1).

220001921 is an equidigital number, since it uses as much as digits as its factorization.

220001921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 220001921 is about 14832.4617309468. The cubic root of 220001921 is about 603.6828307524.

Adding to 220001921 its reverse (129100022), we get a palindrome (349101943).

The spelling of 220001921 in words is "two hundred twenty million, one thousand, nine hundred twenty-one".