121238721 has 16 divisors (see below), whose sum is σ = 179963200. Its totient is φ = 80668224.

The previous prime is 121238707. The next prime is 121238723. The reversal of 121238721 is 127832121.

It is not a de Polignac number, because 121238721 - 2⁹ = 121238209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121238723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10665 + ... + 18873.

It is an arithmetic number, because the mean of its divisors is an integer number (11247700).

Almost surely, 2^121238721 is an apocalyptic number.

It is an amenable number.

121238721 is a deficient number, since it is larger than the sum of its proper divisors (58724479).

121238721 is an equidigital number, since it uses as much as digits as its factorization.

121238721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8765 (or 8759 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 121238721 is about 11010.8456078541. The cubic root of 121238721 is about 494.9338019831.

The spelling of 121238721 in words is "one hundred twenty-one million, two hundred thirty-eight thousand, seven hundred twenty-one".