20984993 has 4 divisors (see below), whose sum is σ = 21897408. Its totient is φ = 20072580.

The previous prime is 20984963. The next prime is 20985001. The reversal of 20984993 is 39948902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20984993 - 2¹⁰ = 20983969 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20984933) 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, 456173 + ... + 456218.

It is an arithmetic number, because the mean of its divisors is an integer number (5474352).

Almost surely, 2^20984993 is an apocalyptic number.

20984993 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20984993 is a deficient number, since it is larger than the sum of its proper divisors (912415).

20984993 is an equidigital number, since it uses as much as digits as its factorization.

20984993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912414.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 20984993 is about 4580.9380043829. The cubic root of 20984993 is about 275.8266826516.

The spelling of 20984993 in words is "twenty million, nine hundred eighty-four thousand, nine hundred ninety-three".