21613889 has 4 divisors (see below), whose sum is σ = 23578800. Its totient is φ = 19648980.

The previous prime is 21613873. The next prime is 21613897. The reversal of 21613889 is 98831612.

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 21613889 - 2⁴ = 21613873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21613819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 982439 + ... + 982460.

It is an arithmetic number, because the mean of its divisors is an integer number (5894700).

Almost surely, 2^21613889 is an apocalyptic number.

It is an amenable number.

21613889 is a deficient number, since it is larger than the sum of its proper divisors (1964911).

21613889 is a wasteful number, since it uses less digits than its factorization.

21613889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1964910.

The product of its digits is 20736, while the sum is 38.

The square root of 21613889 is about 4649.0739938186. The cubic root of 21613889 is about 278.5550089192. Note that the first 3 decimals are identical.

The spelling of 21613889 in words is "twenty-one million, six hundred thirteen thousand, eight hundred eighty-nine".