21023473 has 2 divisors, whose sum is σ = 21023474. Its totient is φ = 21023472.

The previous prime is 21023459. The next prime is 21023501. The reversal of 21023473 is 37432012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19784704 + 1238769 = 4448^2 + 1113^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21023473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21023413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511736 + 10511737.

It is an arithmetic number, because the mean of its divisors is an integer number (10511737).

Almost surely, 2^21023473 is an apocalyptic number.

It is an amenable number.

21023473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023473 is an equidigital number, since it uses as much as digits as its factorization.

21023473 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21023473 is about 4585.1360939453. The cubic root of 21023473 is about 275.9951733736.

Adding to 21023473 its reverse (37432012), we get a palindrome (58455485).

The spelling of 21023473 in words is "twenty-one million, twenty-three thousand, four hundred seventy-three".