1221122257 has 4 divisors (see below), whose sum is σ = 1292952996. Its totient is φ = 1149291520.

The previous prime is 1221122239. The next prime is 1221122281. The reversal of 1221122257 is 7522211221.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 827655361 + 393466896 = 28769^2 + 19836^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221122257 - 2²³ = 1212733649 is a prime.

It is a super-2 number, since 2×1221122257² = 2982279133081548098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221122207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35915344 + ... + 35915377.

It is an arithmetic number, because the mean of its divisors is an integer number (323238249).

Almost surely, 2^1221122257 is an apocalyptic number.

1221122257 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1221122257 is a deficient number, since it is larger than the sum of its proper divisors (71830739).

1221122257 is an equidigital number, since it uses as much as digits as its factorization.

1221122257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71830738.

The product of its digits is 1120, while the sum is 25.

The square root of 1221122257 is about 34944.5597625725. The cubic root of 1221122257 is about 1068.8572704385.

Adding to 1221122257 its reverse (7522211221), we get a palindrome (8743333478).

The spelling of 1221122257 in words is "one billion, two hundred twenty-one million, one hundred twenty-two thousand, two hundred fifty-seven".