121721659 has 2 divisors, whose sum is σ = 121721660. Its totient is φ = 121721658.

The previous prime is 121721653. The next prime is 121721687. The reversal of 121721659 is 956127121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121721659 - 2¹³ = 121713467 is a prime.

It is not a weakly prime, because it can be changed into another prime (121721653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60860829 + 60860830.

It is an arithmetic number, because the mean of its divisors is an integer number (60860830).

Almost surely, 2^121721659 is an apocalyptic number.

121721659 is a deficient number, since it is larger than the sum of its proper divisors (1).

121721659 is an equidigital number, since it uses as much as digits as its factorization.

121721659 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 121721659 is about 11032.7539173137. The cubic root of 121721659 is about 495.5900985523.

It can be divided in two parts, 12172 and 1659, that added together give a palindrome (13831).

The spelling of 121721659 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, six hundred fifty-nine".