21394989 has 64 divisors (see below), whose sum is σ = 40642560. Its totient is φ = 10800000.

The previous prime is 21394949. The next prime is 21395021. The reversal of 21394989 is 98949312.

It is not a de Polignac number, because 21394989 - 2⁸ = 21394733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394949) 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 63 ways as a sum of consecutive naturals, for example, 85114 + ... + 85364.

It is an arithmetic number, because the mean of its divisors is an integer number (635040).

Almost surely, 2^21394989 is an apocalyptic number.

It is an amenable number.

21394989 is a deficient number, since it is larger than the sum of its proper divisors (19247571).

21394989 is a wasteful number, since it uses less digits than its factorization.

21394989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319 (or 313 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 21394989 is about 4625.4717597235. The cubic root of 21394989 is about 277.6114380770.

The spelling of 21394989 in words is "twenty-one million, three hundred ninety-four thousand, nine hundred eighty-nine".