21124993 has 2 divisors, whose sum is σ = 21124994. Its totient is φ = 21124992.

The previous prime is 21124973. The next prime is 21125003. The reversal of 21124993 is 39942112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 121104 = 4583^2 + 348^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124993 - 2¹³ = 21116801 is a prime.

It is not a weakly prime, because it can be changed into another prime (21124973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562496 + 10562497.

It is an arithmetic number, because the mean of its divisors is an integer number (10562497).

Almost surely, 2^21124993 is an apocalyptic number.

It is an amenable number.

21124993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124993 is an equidigital number, since it uses as much as digits as its factorization.

21124993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 31.

The square root of 21124993 is about 4596.1933162129. The cubic root of 21124993 is about 276.4387101503.

The spelling of 21124993 in words is "twenty-one million, one hundred twenty-four thousand, nine hundred ninety-three".