20870987 has 8 divisors (see below), whose sum is σ = 22166160. Its totient is φ = 19595520.

The previous prime is 20870939. The next prime is 20871001. The reversal of 20870987 is 78907802.

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 20870987 - 2¹⁶ = 20805451 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20870887) 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, 2714 + ... + 7007.

It is an arithmetic number, because the mean of its divisors is an integer number (2770770).

Almost surely, 2^20870987 is an apocalyptic number.

20870987 is a deficient number, since it is larger than the sum of its proper divisors (1295173).

20870987 is a wasteful number, since it uses less digits than its factorization.

20870987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9853.

The product of its (nonzero) digits is 56448, while the sum is 41.

The square root of 20870987 is about 4568.4775363353. The cubic root of 20870987 is about 275.3262771940.

The spelling of 20870987 in words is "twenty million, eight hundred seventy thousand, nine hundred eighty-seven".