121225721 has 4 divisors (see below), whose sum is σ = 121708944. Its totient is φ = 120742500.

The previous prime is 121225703. The next prime is 121225763. The reversal of 121225721 is 127522121.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121225721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121225121) 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, 241235 + ... + 241736.

It is an arithmetic number, because the mean of its divisors is an integer number (30427236).

Almost surely, 2^121225721 is an apocalyptic number.

It is an amenable number.

121225721 is a deficient number, since it is larger than the sum of its proper divisors (483223).

121225721 is an equidigital number, since it uses as much as digits as its factorization.

121225721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 483222.

The product of its digits is 560, while the sum is 23.

The square root of 121225721 is about 11010.2552649791. The cubic root of 121225721 is about 494.9161113494.

Adding to 121225721 its reverse (127522121), we get a palindrome (248747842).

The spelling of 121225721 in words is "one hundred twenty-one million, two hundred twenty-five thousand, seven hundred twenty-one".