21336673 has 4 divisors (see below), whose sum is σ = 21346480. Its totient is φ = 21326868.

The previous prime is 21336671. The next prime is 21336697. The reversal of 21336673 is 37663312.

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 21336673 - 2¹ = 21336671 is a prime.

It is a super-2 number, since 2×21336673² = 910507229417858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21336671) 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, 15 + ... + 6532.

It is an arithmetic number, because the mean of its divisors is an integer number (5336620).

Almost surely, 2^21336673 is an apocalyptic number.

It is an amenable number.

21336673 is a deficient number, since it is larger than the sum of its proper divisors (9807).

21336673 is an equidigital number, since it uses as much as digits as its factorization.

21336673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9806.

The product of its digits is 13608, while the sum is 31.

The square root of 21336673 is about 4619.1636688907. The cubic root of 21336673 is about 277.3589814572.

Adding to 21336673 its reverse (37663312), we get a palindrome (58999985).

The spelling of 21336673 in words is "twenty-one million, three hundred thirty-six thousand, six hundred seventy-three".