20984387 has 4 divisors (see below), whose sum is σ = 21472440. Its totient is φ = 20496336.

The previous prime is 20984377. The next prime is 20984389. The reversal of 20984387 is 78348902.

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 20984387 - 2¹⁰ = 20983363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20984389) 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, 243962 + ... + 244047.

It is an arithmetic number, because the mean of its divisors is an integer number (5368110).

Almost surely, 2^20984387 is an apocalyptic number.

20984387 is a deficient number, since it is larger than the sum of its proper divisors (488053).

20984387 is an equidigital number, since it uses as much as digits as its factorization.

20984387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488052.

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 20984387 is about 4580.8718602467. The cubic root of 20984387 is about 275.8240275386.

The spelling of 20984387 in words is "twenty million, nine hundred eighty-four thousand, three hundred eighty-seven".