20213987 has 4 divisors (see below), whose sum is σ = 21092880. Its totient is φ = 19335096.

The previous prime is 20213983. The next prime is 20214001. The reversal of 20213987 is 78931202.

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 20213987 - 2² = 20213983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20213981) 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, 439412 + ... + 439457.

It is an arithmetic number, because the mean of its divisors is an integer number (5273220).

Almost surely, 2^20213987 is an apocalyptic number.

20213987 is a deficient number, since it is larger than the sum of its proper divisors (878893).

20213987 is an equidigital number, since it uses as much as digits as its factorization.

20213987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878892.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 20213987 is about 4495.9967749099. The cubic root of 20213987 is about 272.4064128865.

The spelling of 20213987 in words is "twenty million, two hundred thirteen thousand, nine hundred eighty-seven".