21224293 has 2 divisors, whose sum is σ = 21224294. Its totient is φ = 21224292.

The previous prime is 21224267. The next prime is 21224297. The reversal of 21224293 is 39242212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13118884 + 8105409 = 3622^2 + 2847^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21224293 is a prime.

It is a super-2 number, since 2×21224293² = 900941226699698, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21224297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612146 + 10612147.

It is an arithmetic number, because the mean of its divisors is an integer number (10612147).

Almost surely, 2^21224293 is an apocalyptic number.

It is an amenable number.

21224293 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224293 is an equidigital number, since it uses as much as digits as its factorization.

21224293 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 25.

The square root of 21224293 is about 4606.9830692113. The cubic root of 21224293 is about 276.8711752228.

The spelling of 21224293 in words is "twenty-one million, two hundred twenty-four thousand, two hundred ninety-three".