126921217 has 2 divisors, whose sum is σ = 126921218. Its totient is φ = 126921216.

The previous prime is 126921173. The next prime is 126921241. The reversal of 126921217 is 712129621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85396081 + 41525136 = 9241^2 + 6444^2 .

It is a cyclic number.

It is not a de Polignac number, because 126921217 - 2⁷ = 126921089 is a prime.

It is a super-2 number, since 2×126921217² = 32217990649522178, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (126921247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63460608 + 63460609.

It is an arithmetic number, because the mean of its divisors is an integer number (63460609).

Almost surely, 2^126921217 is an apocalyptic number.

It is an amenable number.

126921217 is a deficient number, since it is larger than the sum of its proper divisors (1).

126921217 is an equidigital number, since it uses as much as digits as its factorization.

126921217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 31.

The square root of 126921217 is about 11265.9316969348. The cubic root of 126921217 is about 502.5486097708.

The spelling of 126921217 in words is "one hundred twenty-six million, nine hundred twenty-one thousand, two hundred seventeen".