21053189 has 4 divisors (see below), whose sum is σ = 21179424. Its totient is φ = 20926956.

The previous prime is 21053173. The next prime is 21053203. The reversal of 21053189 is 98135012.

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 21053189 - 2⁴ = 21053173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21053129) 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, 62867 + ... + 63200.

It is an arithmetic number, because the mean of its divisors is an integer number (5294856).

Almost surely, 2^21053189 is an apocalyptic number.

It is an amenable number.

21053189 is a deficient number, since it is larger than the sum of its proper divisors (126235).

21053189 is a wasteful number, since it uses less digits than its factorization.

21053189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126234.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 21053189 is about 4588.3754205601. The cubic root of 21053189 is about 276.1251489082.

It can be divided in two parts, 2 and 1053189, that multiplied together give a triangular number (2106378 = T₂₀₅₂).

The spelling of 21053189 in words is "twenty-one million, fifty-three thousand, one hundred eighty-nine".