21047933 has 6 divisors (see below), whose sum is σ = 21276666. Its totient is φ = 20821632.

The previous prime is 21047927. The next prime is 21047951. The reversal of 21047933 is 33974012.

It can be written as a sum of positive squares in 3 ways, for example, as 4831204 + 16216729 = 2198^2 + 4027^2 .

It is not a de Polignac number, because 21047933 - 2¹⁶ = 20982397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21047896 and 21047905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047333) 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, 8291 + ... + 10527.

It is an arithmetic number, because the mean of its divisors is an integer number (3546111).

Almost surely, 2^21047933 is an apocalyptic number.

It is an amenable number.

21047933 is a deficient number, since it is larger than the sum of its proper divisors (228733).

21047933 is an frugal number, since it uses more digits than its factorization.

21047933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2431 (or 2334 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 21047933 is about 4587.8026330696. The cubic root of 21047933 is about 276.1021684693.

The spelling of 21047933 in words is "twenty-one million, forty-seven thousand, nine hundred thirty-three".