121659721 has 2 divisors, whose sum is σ = 121659722. Its totient is φ = 121659720.

The previous prime is 121659709. The next prime is 121659731. The reversal of 121659721 is 127956121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99201600 + 22458121 = 9960^2 + 4739^2 .

It is a cyclic number.

It is not a de Polignac number, because 121659721 - 2⁵ = 121659689 is a prime.

It is not a weakly prime, because it can be changed into another prime (121659731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60829860 + 60829861.

It is an arithmetic number, because the mean of its divisors is an integer number (60829861).

Almost surely, 2^121659721 is an apocalyptic number.

It is an amenable number.

121659721 is a deficient number, since it is larger than the sum of its proper divisors (1).

121659721 is an equidigital number, since it uses as much as digits as its factorization.

121659721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 34.

The square root of 121659721 is about 11029.9465547209. The cubic root of 121659721 is about 495.5060240395.

The spelling of 121659721 in words is "one hundred twenty-one million, six hundred fifty-nine thousand, seven hundred twenty-one".