1221669377 has 2 divisors, whose sum is σ = 1221669378. Its totient is φ = 1221669376.

The previous prime is 1221669347. The next prime is 1221669389. The reversal of 1221669377 is 7739661221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1194462721 + 27206656 = 34561^2 + 5216^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221669377 - 2¹⁰ = 1221668353 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221669347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610834688 + 610834689.

It is an arithmetic number, because the mean of its divisors is an integer number (610834689).

Almost surely, 2^1221669377 is an apocalyptic number.

It is an amenable number.

1221669377 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221669377 is an equidigital number, since it uses as much as digits as its factorization.

1221669377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 190512, while the sum is 44.

The square root of 1221669377 is about 34952.3872861354. The cubic root of 1221669377 is about 1069.0168793201.

The spelling of 1221669377 in words is "one billion, two hundred twenty-one million, six hundred sixty-nine thousand, three hundred seventy-seven".