121206721 has 4 divisors (see below), whose sum is σ = 121816000. Its totient is φ = 120597444.

The previous prime is 121206713. The next prime is 121206731. The reversal of 121206721 is 127602121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 127602121 = 7883 ⋅16187.

It is a cyclic number.

It is not a de Polignac number, because 121206721 - 2³ = 121206713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121206692 and 121206701.

It is not an unprimeable number, because it can be changed into a prime (121206731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304341 + ... + 304738.

It is an arithmetic number, because the mean of its divisors is an integer number (30454000).

Almost surely, 2^121206721 is an apocalyptic number.

It is an amenable number.

121206721 is a deficient number, since it is larger than the sum of its proper divisors (609279).

121206721 is an equidigital number, since it uses as much as digits as its factorization.

121206721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609278.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 121206721 is about 11009.3923992199. The cubic root of 121206721 is about 494.8902535327.

Adding to 121206721 its reverse (127602121), we get a palindrome (248808842).

The spelling of 121206721 in words is "one hundred twenty-one million, two hundred six thousand, seven hundred twenty-one".