220631809 has 2 divisors, whose sum is σ = 220631810. Its totient is φ = 220631808.

The previous prime is 220631759. The next prime is 220631813. The reversal of 220631809 is 908136022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 139901584 + 80730225 = 11828^2 + 8985^2 .

It is a cyclic number.

It is not a de Polignac number, because 220631809 - 2⁹ = 220631297 is a prime.

It is a super-2 number, since 2×220631809² = 97356790285224962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (220631849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110315904 + 110315905.

It is an arithmetic number, because the mean of its divisors is an integer number (110315905).

Almost surely, 2^220631809 is an apocalyptic number.

It is an amenable number.

220631809 is a deficient number, since it is larger than the sum of its proper divisors (1).

220631809 is an equidigital number, since it uses as much as digits as its factorization.

220631809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 220631809 is about 14853.6799817419. The cubic root of 220631809 is about 604.2584170089.

The spelling of 220631809 in words is "two hundred twenty million, six hundred thirty-one thousand, eight hundred nine".