121221987 has 4 divisors (see below), whose sum is σ = 161629320. Its totient is φ = 80814656.

The previous prime is 121221979. The next prime is 121222007. The reversal of 121221987 is 789122121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 121221987 - 2³ = 121221979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121231987) 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, 20203662 + ... + 20203667.

It is an arithmetic number, because the mean of its divisors is an integer number (40407330).

Almost surely, 2^121221987 is an apocalyptic number.

121221987 is a deficient number, since it is larger than the sum of its proper divisors (40407333).

121221987 is an equidigital number, since it uses as much as digits as its factorization.

121221987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40407332.

The product of its digits is 4032, while the sum is 33.

The square root of 121221987 is about 11010.0856944894. The cubic root of 121221987 is about 494.9110298213.

The spelling of 121221987 in words is "one hundred twenty-one million, two hundred twenty-one thousand, nine hundred eighty-seven".