21028597 has 2 divisors, whose sum is σ = 21028598. Its totient is φ = 21028596.

The previous prime is 21028549. The next prime is 21028619. The reversal of 21028597 is 79582012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20124196 + 904401 = 4486^2 + 951^2 .

It is a cyclic number.

It is not a de Polignac number, because 21028597 - 2¹¹ = 21026549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21028517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10514298 + 10514299.

It is an arithmetic number, because the mean of its divisors is an integer number (10514299).

Almost surely, 2^21028597 is an apocalyptic number.

It is an amenable number.

21028597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21028597 is an equidigital number, since it uses as much as digits as its factorization.

21028597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 21028597 is about 4585.6948219436. The cubic root of 21028597 is about 276.0175940965.

The spelling of 21028597 in words is "twenty-one million, twenty-eight thousand, five hundred ninety-seven".