1220421557 has 2 divisors, whose sum is σ = 1220421558. Its totient is φ = 1220421556.

The previous prime is 1220421541. The next prime is 1220421589. The reversal of 1220421557 is 7551240221.

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., 910168561 + 310252996 = 30169^2 + 17614^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220421557 - 2⁴ = 1220421541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220421157) 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, 610210778 + 610210779.

It is an arithmetic number, because the mean of its divisors is an integer number (610210779).

Almost surely, 2^1220421557 is an apocalyptic number.

It is an amenable number.

1220421557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220421557 is an equidigital number, since it uses as much as digits as its factorization.

1220421557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5600, while the sum is 29.

The square root of 1220421557 is about 34934.5324428423. The cubic root of 1220421557 is about 1068.6527887050.

Adding to 1220421557 its reverse (7551240221), we get a palindrome (8771661778).

The spelling of 1220421557 in words is "one billion, two hundred twenty million, four hundred twenty-one thousand, five hundred fifty-seven".