20893921 has 4 divisors (see below), whose sum is σ = 20903344. Its totient is φ = 20884500.

The previous prime is 20893919. The next prime is 20893927. The reversal of 20893921 is 12939802.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20893921 - 2¹ = 20893919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20893927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 646 + ... + 6496.

It is an arithmetic number, because the mean of its divisors is an integer number (5225836).

Almost surely, 2^20893921 is an apocalyptic number.

It is an amenable number.

20893921 is a deficient number, since it is larger than the sum of its proper divisors (9423).

20893921 is an equidigital number, since it uses as much as digits as its factorization.

20893921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9422.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 20893921 is about 4570.9868737506. The cubic root of 20893921 is about 275.4270873350.

The spelling of 20893921 in words is "twenty million, eight hundred ninety-three thousand, nine hundred twenty-one".