1221417817 has 2 divisors, whose sum is σ = 1221417818. Its totient is φ = 1221417816.

The previous prime is 1221417809. The next prime is 1221417833. The reversal of 1221417817 is 7187141221.

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., 1018184281 + 203233536 = 31909^2 + 14256^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221417817 - 2³ = 1221417809 is a prime.

It is a super-2 number, since 2×1221417817² = 2983722967370090978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221417877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610708908 + 610708909.

It is an arithmetic number, because the mean of its divisors is an integer number (610708909).

Almost surely, 2^1221417817 is an apocalyptic number.

It is an amenable number.

1221417817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221417817 is an equidigital number, since it uses as much as digits as its factorization.

1221417817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6272, while the sum is 34.

The square root of 1221417817 is about 34948.7884911623. The cubic root of 1221417817 is about 1068.9434987608.

The spelling of 1221417817 in words is "one billion, two hundred twenty-one million, four hundred seventeen thousand, eight hundred seventeen".