21745063 has 4 divisors (see below), whose sum is σ = 22889560. Its totient is φ = 20600568.

The previous prime is 21745039. The next prime is 21745069. The reversal of 21745063 is 36054712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21745063 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 (21745069) 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, 572220 + ... + 572257.

It is an arithmetic number, because the mean of its divisors is an integer number (5722390).

Almost surely, 2^21745063 is an apocalyptic number.

21745063 is a deficient number, since it is larger than the sum of its proper divisors (1144497).

21745063 is a wasteful number, since it uses less digits than its factorization.

21745063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1144496.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21745063 is about 4663.1601945462. The cubic root of 21745063 is about 279.1173865737.

Adding to 21745063 its reverse (36054712), we get a palindrome (57799775).

The spelling of 21745063 in words is "twenty-one million, seven hundred forty-five thousand, sixty-three".