21249073 has 2 divisors, whose sum is σ = 21249074. Its totient is φ = 21249072.

The previous prime is 21249047. The next prime is 21249077. The reversal of 21249073 is 37094212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17740944 + 3508129 = 4212^2 + 1873^2 .

It is a cyclic number.

It is not a de Polignac number, because 21249073 - 2¹³ = 21240881 is a prime.

It is not a weakly prime, because it can be changed into another prime (21249077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10624536 + 10624537.

It is an arithmetic number, because the mean of its divisors is an integer number (10624537).

Almost surely, 2^21249073 is an apocalyptic number.

It is an amenable number.

21249073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21249073 is an equidigital number, since it uses as much as digits as its factorization.

21249073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21249073 is about 4609.6716802827. The cubic root of 21249073 is about 276.9788851217.

The spelling of 21249073 in words is "twenty-one million, two hundred forty-nine thousand, seventy-three".