220018921 has 2 divisors, whose sum is σ = 220018922. Its totient is φ = 220018920.

The previous prime is 220018837. The next prime is 220018937. The reversal of 220018921 is 129810022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164352400 + 55666521 = 12820^2 + 7461^2 .

It is a cyclic number.

It is not a de Polignac number, because 220018921 - 2⁷ = 220018793 is a prime.

It is not a weakly prime, because it can be changed into another prime (220018951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110009460 + 110009461.

It is an arithmetic number, because the mean of its divisors is an integer number (110009461).

Almost surely, 2^220018921 is an apocalyptic number.

It is an amenable number.

220018921 is a deficient number, since it is larger than the sum of its proper divisors (1).

220018921 is an equidigital number, since it uses as much as digits as its factorization.

220018921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 220018921 is about 14833.0347872578. The cubic root of 220018921 is about 603.6983796224.

Adding to 220018921 its reverse (129810022), we get a palindrome (349828943).

The spelling of 220018921 in words is "two hundred twenty million, eighteen thousand, nine hundred twenty-one".