21097673 has 4 divisors (see below), whose sum is σ = 21107328. Its totient is φ = 21088020.

The previous prime is 21097667. The next prime is 21097723. The reversal of 21097673 is 37679012.

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 21097673 - 2¹² = 21093577 is a prime.

It is a super-2 number, since 2×21097673² = 890223612029858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21097603) 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, 188 + ... + 6498.

It is an arithmetic number, because the mean of its divisors is an integer number (5276832).

Almost surely, 2^21097673 is an apocalyptic number.

It is an amenable number.

21097673 is a deficient number, since it is larger than the sum of its proper divisors (9655).

21097673 is an equidigital number, since it uses as much as digits as its factorization.

21097673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9654.

The product of its (nonzero) digits is 15876, while the sum is 35.

The square root of 21097673 is about 4593.2203300081. The cubic root of 21097673 is about 276.3194901725.

The spelling of 21097673 in words is "twenty-one million, ninety-seven thousand, six hundred seventy-three".