21298597 has 4 divisors (see below), whose sum is σ = 21321900. Its totient is φ = 21275296.

The previous prime is 21298583. The next prime is 21298681. The reversal of 21298597 is 79589212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5924356 + 15374241 = 2434^2 + 3921^2 .

It is a cyclic number.

It is not a de Polignac number, because 21298597 - 2²³ = 12909989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21298517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10222 + ... + 12127.

It is an arithmetic number, because the mean of its divisors is an integer number (5330475).

Almost surely, 2^21298597 is an apocalyptic number.

It is an amenable number.

21298597 is a deficient number, since it is larger than the sum of its proper divisors (23303).

21298597 is an equidigital number, since it uses as much as digits as its factorization.

21298597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23302.

The product of its digits is 90720, while the sum is 43.

The square root of 21298597 is about 4615.0403031826. The cubic root of 21298597 is about 277.1938977881.

The spelling of 21298597 in words is "twenty-one million, two hundred ninety-eight thousand, five hundred ninety-seven".