21058997 has 2 divisors, whose sum is σ = 21058998. Its totient is φ = 21058996.

The previous prime is 21058993. The next prime is 21059021. The reversal of 21058997 is 79985012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19989841 + 1069156 = 4471^2 + 1034^2 .

It is a cyclic number.

It is not a de Polignac number, because 21058997 - 2² = 21058993 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21058993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10529498 + 10529499.

It is an arithmetic number, because the mean of its divisors is an integer number (10529499).

Almost surely, 2^21058997 is an apocalyptic number.

It is an amenable number.

21058997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21058997 is an equidigital number, since it uses as much as digits as its factorization.

21058997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 21058997 is about 4589.0082806637. The cubic root of 21058997 is about 276.1505383700.

The spelling of 21058997 in words is "twenty-one million, fifty-eight thousand, nine hundred ninety-seven".