1220420261 has 2 divisors, whose sum is σ = 1220420262. Its totient is φ = 1220420260.

The previous prime is 1220420233. The next prime is 1220420303. The reversal of 1220420261 is 1620240221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 811167361 + 409252900 = 28481^2 + 20230^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220420261 - 2¹⁰ = 1220419237 is a prime.

It is a super-2 number, since 2×1220420261² = 2978851226918616242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220420231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610210130 + 610210131.

It is an arithmetic number, because the mean of its divisors is an integer number (610210131).

Almost surely, 2^1220420261 is an apocalyptic number.

It is an amenable number.

1220420261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220420261 is an equidigital number, since it uses as much as digits as its factorization.

1220420261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 1220420261 is about 34934.5138938557. The cubic root of 1220420261 is about 1068.6524104273.

Adding to 1220420261 its reverse (1620240221), we get a palindrome (2840660482).

The spelling of 1220420261 in words is "one billion, two hundred twenty million, four hundred twenty thousand, two hundred sixty-one".