21037673 has 4 divisors (see below), whose sum is σ = 21763140. Its totient is φ = 20312208.

The previous prime is 21037657. The next prime is 21037699. The reversal of 21037673 is 37673012.

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 8456464 + 12581209 = 2908^2 + 3547^2 .

It is a cyclic number.

It is not a de Polignac number, because 21037673 - 2⁴ = 21037657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 725437 = 21037673 / (2 + 1 + 0 + 3 + 7 + 6 + 7 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21037603) 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, 362690 + ... + 362747.

It is an arithmetic number, because the mean of its divisors is an integer number (5440785).

Almost surely, 2^21037673 is an apocalyptic number.

It is an amenable number.

21037673 is a deficient number, since it is larger than the sum of its proper divisors (725467).

21037673 is an equidigital number, since it uses as much as digits as its factorization.

21037673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725466.

The product of its (nonzero) digits is 5292, while the sum is 29.

The square root of 21037673 is about 4586.6843144040. The cubic root of 21037673 is about 276.0572983678.

The spelling of 21037673 in words is "twenty-one million, thirty-seven thousand, six hundred seventy-three".