21325649 has 4 divisors (see below), whose sum is σ = 21379764. Its totient is φ = 21271536.

The previous prime is 21325637. The next prime is 21325651. The reversal of 21325649 is 94652312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12475024 + 8850625 = 3532^2 + 2975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21325649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21325349) 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, 26462 + ... + 27255.

It is an arithmetic number, because the mean of its divisors is an integer number (5344941).

Almost surely, 2^21325649 is an apocalyptic number.

It is an amenable number.

21325649 is a deficient number, since it is larger than the sum of its proper divisors (54115).

21325649 is an equidigital number, since it uses as much as digits as its factorization.

21325649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54114.

The product of its digits is 12960, while the sum is 32.

The square root of 21325649 is about 4617.9702251097. The cubic root of 21325649 is about 277.3112056215.

The spelling of 21325649 in words is "twenty-one million, three hundred twenty-five thousand, six hundred forty-nine".