21252043 has 6 divisors (see below), whose sum is σ = 21501524. Its totient is φ = 21005424.

The previous prime is 21252031. The next prime is 21252047. The reversal of 21252043 is 34025212.

It is a de Polignac number, because none of the positive numbers 2^k-21252043 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21252043.

It is not an unprimeable number, because it can be changed into a prime (21252047) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6580 + ... + 9262.

Almost surely, 2^21252043 is an apocalyptic number.

21252043 is a deficient number, since it is larger than the sum of its proper divisors (249481).

21252043 is an frugal number, since it uses more digits than its factorization.

21252043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2861 (or 2772 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21252043 is about 4609.9938177833. The cubic root of 21252043 is about 276.9917890410.

Adding to 21252043 its reverse (34025212), we get a palindrome (55277255).

The spelling of 21252043 in words is "twenty-one million, two hundred fifty-two thousand, forty-three".