21052747 has 8 divisors (see below), whose sum is σ = 21494160. Its totient is φ = 20614560.

The previous prime is 21052739. The next prime is 21052769. The reversal of 21052747 is 74725012.

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 21052747 - 2³ = 21052739 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21052547) 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, 15768 + ... + 17050.

It is an arithmetic number, because the mean of its divisors is an integer number (2686770).

Almost surely, 2^21052747 is an apocalyptic number.

21052747 is a deficient number, since it is larger than the sum of its proper divisors (441413).

21052747 is a wasteful number, since it uses less digits than its factorization.

21052747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1613.

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 21052747 is about 4588.3272551116. The cubic root of 21052747 is about 276.1232165300.

Adding to 21052747 its reverse (74725012), we get a palindrome (95777759).

The spelling of 21052747 in words is "twenty-one million, fifty-two thousand, seven hundred forty-seven".