21340673 has 4 divisors (see below), whose sum is σ = 21547968. Its totient is φ = 21133380.

The previous prime is 21340663. The next prime is 21340721. The reversal of 21340673 is 37604312.

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.

It is a cyclic number.

It is not a de Polignac number, because 21340673 - 2¹⁰ = 21339649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21340603) 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, 103493 + ... + 103698.

It is an arithmetic number, because the mean of its divisors is an integer number (5386992).

Almost surely, 2^21340673 is an apocalyptic number.

It is an amenable number.

21340673 is a deficient number, since it is larger than the sum of its proper divisors (207295).

21340673 is a wasteful number, since it uses less digits than its factorization.

21340673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207294.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 21340673 is about 4619.5966274124. The cubic root of 21340673 is about 277.3763125973.

Adding to 21340673 its reverse (37604312), we get a palindrome (58944985).

The spelling of 21340673 in words is "twenty-one million, three hundred forty thousand, six hundred seventy-three".