220136821 has 2 divisors, whose sum is σ = 220136822. Its totient is φ = 220136820.

The previous prime is 220136809. The next prime is 220136843. The reversal of 220136821 is 128631022.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 183060900 + 37075921 = 13530^2 + 6089^2 .

It is a cyclic number.

It is not a de Polignac number, because 220136821 - 2⁹ = 220136309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220134821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110068410 + 110068411.

It is an arithmetic number, because the mean of its divisors is an integer number (110068411).

Almost surely, 2^220136821 is an apocalyptic number.

It is an amenable number.

220136821 is a deficient number, since it is larger than the sum of its proper divisors (1).

220136821 is an equidigital number, since it uses as much as digits as its factorization.

220136821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 220136821 is about 14837.0084922804. The cubic root of 220136821 is about 603.8061935760.

Adding to 220136821 its reverse (128631022), we get a palindrome (348767843).

The spelling of 220136821 in words is "two hundred twenty million, one hundred thirty-six thousand, eight hundred twenty-one".