121717621 has 2 divisors, whose sum is σ = 121717622. Its totient is φ = 121717620.

The previous prime is 121717601. The next prime is 121717663. The reversal of 121717621 is 126717121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108972721 + 12744900 = 10439^2 + 3570^2 .

It is an emirp because it is prime and its reverse (126717121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121717621 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121717621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121717601) 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, 60858810 + 60858811.

It is an arithmetic number, because the mean of its divisors is an integer number (60858811).

Almost surely, 2^121717621 is an apocalyptic number.

It is an amenable number.

121717621 is a deficient number, since it is larger than the sum of its proper divisors (1).

121717621 is an equidigital number, since it uses as much as digits as its factorization.

121717621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1176, while the sum is 28.

The square root of 121717621 is about 11032.5709152491. The cubic root of 121717621 is about 495.5846182486.

The spelling of 121717621 in words is "one hundred twenty-one million, seven hundred seventeen thousand, six hundred twenty-one".