21673793 has 4 divisors (see below), whose sum is σ = 22948740. Its totient is φ = 20398848.

The previous prime is 21673787. The next prime is 21673807. The reversal of 21673793 is 39737612.

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 11478544 + 10195249 = 3388^2 + 3193^2 .

It is a cyclic number.

It is not a de Polignac number, because 21673793 - 2¹⁰ = 21672769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21673703) 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, 637448 + ... + 637481.

It is an arithmetic number, because the mean of its divisors is an integer number (5737185).

Almost surely, 2^21673793 is an apocalyptic number.

It is an amenable number.

21673793 is a deficient number, since it is larger than the sum of its proper divisors (1274947).

21673793 is a wasteful number, since it uses less digits than its factorization.

21673793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1274946.

The product of its digits is 47628, while the sum is 38.

The square root of 21673793 is about 4655.5121093173. The cubic root of 21673793 is about 278.8121146944.

The spelling of 21673793 in words is "twenty-one million, six hundred seventy-three thousand, seven hundred ninety-three".