121439987 has 8 divisors (see below), whose sum is σ = 123112704. Its totient is φ = 119776968.

The previous prime is 121439947. The next prime is 121439999. The reversal of 121439987 is 789934121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121439987 - 2¹⁰ = 121438963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121439947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24848 + ... + 29330.

It is an arithmetic number, because the mean of its divisors is an integer number (15389088).

Almost surely, 2^121439987 is an apocalyptic number.

121439987 is a deficient number, since it is larger than the sum of its proper divisors (1672717).

121439987 is a wasteful number, since it uses less digits than its factorization.

121439987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4849.

The product of its digits is 108864, while the sum is 44.

The square root of 121439987 is about 11019.9812613271. The cubic root of 121439987 is about 495.2075271718.

The spelling of 121439987 in words is "one hundred twenty-one million, four hundred thirty-nine thousand, nine hundred eighty-seven".