220402561 has 2 divisors, whose sum is σ = 220402562. Its totient is φ = 220402560.

The previous prime is 220402543. The next prime is 220402573. The reversal of 220402561 is 165204022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 218596225 + 1806336 = 14785^2 + 1344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-220402561 is a prime.

It is equal to p_12143416 and since 220402561 and 12143416 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (220402661) 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, 110201280 + 110201281.

It is an arithmetic number, because the mean of its divisors is an integer number (110201281).

Almost surely, 2^220402561 is an apocalyptic number.

220402561 is the 7936-th centered heptagonal number.

It is an amenable number.

220402561 is a deficient number, since it is larger than the sum of its proper divisors (1).

220402561 is an equidigital number, since it uses as much as digits as its factorization.

220402561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 220402561 is about 14845.9611005822. The cubic root of 220402561 is about 604.0490591045.

Adding to 220402561 its reverse (165204022), we get a palindrome (385606583).

The spelling of 220402561 in words is "two hundred twenty million, four hundred two thousand, five hundred sixty-one".