21054245 has 8 divisors (see below), whose sum is σ = 26751384. Its totient is φ = 15852544.

The previous prime is 21054233. The next prime is 21054247. The reversal of 21054245 is 54245012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10407076 + 10647169 = 3226^2 + 3263^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21054245 - 2⁶ = 21054181 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21054245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123764 + ... + 123933.

It is an arithmetic number, because the mean of its divisors is an integer number (3343923).

Almost surely, 2^21054245 is an apocalyptic number.

It is an amenable number.

21054245 is a deficient number, since it is larger than the sum of its proper divisors (5697139).

21054245 is a wasteful number, since it uses less digits than its factorization.

21054245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247719.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 21054245 is about 4588.4904925258. The cubic root of 21054245 is about 276.1297655213.

Adding to 21054245 its reverse (54245012), we get a palindrome (75299257).

The spelling of 21054245 in words is "twenty-one million, fifty-four thousand, two hundred forty-five".