21056597 has 2 divisors, whose sum is σ = 21056598. Its totient is φ = 21056596.

The previous prime is 21056593. The next prime is 21056653. The reversal of 21056597 is 79565012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12348196 + 8708401 = 3514^2 + 2951^2 .

It is a cyclic number.

It is not a de Polignac number, because 21056597 - 2² = 21056593 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21056593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10528298 + 10528299.

It is an arithmetic number, because the mean of its divisors is an integer number (10528299).

Almost surely, 2^21056597 is an apocalyptic number.

It is an amenable number.

21056597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21056597 is an equidigital number, since it uses as much as digits as its factorization.

21056597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 21056597 is about 4588.7467788057. The cubic root of 21056597 is about 276.1400474229.

The spelling of 21056597 in words is "twenty-one million, fifty-six thousand, five hundred ninety-seven".