121721947 has 2 divisors, whose sum is σ = 121721948. Its totient is φ = 121721946.

The previous prime is 121721933. The next prime is 121721953. The reversal of 121721947 is 749127121.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121721947 is a prime.

It is not a weakly prime, because it can be changed into another prime (121721917) 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, 60860973 + 60860974.

It is an arithmetic number, because the mean of its divisors is an integer number (60860974).

Almost surely, 2^121721947 is an apocalyptic number.

121721947 is a deficient number, since it is larger than the sum of its proper divisors (1).

121721947 is an equidigital number, since it uses as much as digits as its factorization.

121721947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 34.

The square root of 121721947 is about 11032.7669693509. The cubic root of 121721947 is about 495.5904894162.

The spelling of 121721947 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, nine hundred forty-seven".