220121581 has 2 divisors, whose sum is σ = 220121582. Its totient is φ = 220121580.

The previous prime is 220121563. The next prime is 220121597. The reversal of 220121581 is 185121022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213014025 + 7107556 = 14595^2 + 2666^2 .

It is a cyclic number.

It is not a de Polignac number, because 220121581 - 2⁵ = 220121549 is a prime.

It is a super-2 number, since 2×220121581² = 96907020843879122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220121381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110060790 + 110060791.

It is an arithmetic number, because the mean of its divisors is an integer number (110060791).

Almost surely, 2^220121581 is an apocalyptic number.

It is an amenable number.

220121581 is a deficient number, since it is larger than the sum of its proper divisors (1).

220121581 is an equidigital number, since it uses as much as digits as its factorization.

220121581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 220121581 is about 14836.4949027727. The cubic root of 220121581 is about 603.7922594861.

It can be divided in two parts, 220 and 121581, that added together give a square (121801 = 349²).

The spelling of 220121581 in words is "two hundred twenty million, one hundred twenty-one thousand, five hundred eighty-one".