21124073 has 2 divisors, whose sum is σ = 21124074. Its totient is φ = 21124072.

The previous prime is 21124069. The next prime is 21124079. The reversal of 21124073 is 37042112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20187049 + 937024 = 4493^2 + 968^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124073 - 2² = 21124069 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21124079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562036 + 10562037.

It is an arithmetic number, because the mean of its divisors is an integer number (10562037).

Almost surely, 2^21124073 is an apocalyptic number.

It is an amenable number.

21124073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124073 is an equidigital number, since it uses as much as digits as its factorization.

21124073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21124073 is about 4596.0932323007. The cubic root of 21124073 is about 276.4346970948.

Adding to 21124073 its reverse (37042112), we get a palindrome (58166185).

The spelling of 21124073 in words is "twenty-one million, one hundred twenty-four thousand, seventy-three".