21106597 has 4 divisors (see below), whose sum is σ = 21116736. Its totient is φ = 21096460.

The previous prime is 21106583. The next prime is 21106607. The reversal of 21106597 is 79560112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21106597 - 2¹¹ = 21104549 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21106097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 679 + ... + 6532.

It is an arithmetic number, because the mean of its divisors is an integer number (5279184).

Almost surely, 2^21106597 is an apocalyptic number.

It is an amenable number.

21106597 is a deficient number, since it is larger than the sum of its proper divisors (10139).

21106597 is an equidigital number, since it uses as much as digits as its factorization.

21106597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10138.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 21106597 is about 4594.1916590408. The cubic root of 21106597 is about 276.3584443506.

The spelling of 21106597 in words is "twenty-one million, one hundred six thousand, five hundred ninety-seven".