1221121177 has 2 divisors, whose sum is σ = 1221121178. Its totient is φ = 1221121176.

The previous prime is 1221121123. The next prime is 1221121189. The reversal of 1221121177 is 7711211221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 987153561 + 233967616 = 31419^2 + 15296^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221121177 is a prime.

It is a super-2 number, since 2×1221121177² = 2982273857835730658, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221121117) 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 as a sum of consecutive naturals, namely, 610560588 + 610560589.

It is an arithmetic number, because the mean of its divisors is an integer number (610560589).

Almost surely, 2^1221121177 is an apocalyptic number.

It is an amenable number.

1221121177 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221121177 is an equidigital number, since it uses as much as digits as its factorization.

1221121177 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 392, while the sum is 25.

The square root of 1221121177 is about 34944.5443095199. The cubic root of 1221121177 is about 1068.8569553278.

Adding to 1221121177 its reverse (7711211221), we get a palindrome (8932332398).

The spelling of 1221121177 in words is "one billion, two hundred twenty-one million, one hundred twenty-one thousand, one hundred seventy-seven".