21189601 has 4 divisors (see below), whose sum is σ = 22110912. Its totient is φ = 20268292.

The previous prime is 21189593. The next prime is 21189607. The reversal of 21189601 is 10698112.

It is a happy number.

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 21189601 - 2³ = 21189593 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21189601.

It is not an unprimeable number, because it can be changed into a prime (21189607) 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, 460621 + ... + 460666.

It is an arithmetic number, because the mean of its divisors is an integer number (5527728).

Almost surely, 2^21189601 is an apocalyptic number.

It is an amenable number.

21189601 is a deficient number, since it is larger than the sum of its proper divisors (921311).

21189601 is an equidigital number, since it uses as much as digits as its factorization.

21189601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 921310.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 21189601 is about 4603.2163755357. The cubic root of 21189601 is about 276.7202404277.

The spelling of 21189601 in words is "twenty-one million, one hundred eighty-nine thousand, six hundred one".