121721215 has 32 divisors (see below), whose sum is σ = 182767104. Its totient is φ = 75603840.

The previous prime is 121721209. The next prime is 121721219. The reversal of 121721215 is 512127121.

It is not a de Polignac number, because 121721215 - 2¹⁵ = 121688447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121721219) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 179457 + ... + 180133.

It is an arithmetic number, because the mean of its divisors is an integer number (5711472).

Almost surely, 2^121721215 is an apocalyptic number.

121721215 is a deficient number, since it is larger than the sum of its proper divisors (61045889).

121721215 is a wasteful number, since it uses less digits than its factorization.

121721215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1167.

The product of its digits is 280, while the sum is 22.

The square root of 121721215 is about 11032.7337953927. The cubic root of 121721215 is about 495.5894959691.

Adding to 121721215 its reverse (512127121), we get a palindrome (633848336).

The spelling of 121721215 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, two hundred fifteen".