21673451 has 4 divisors (see below), whose sum is σ = 21872400. Its totient is φ = 21474504.

The previous prime is 21673423. The next prime is 21673459. The reversal of 21673451 is 15437612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21673451 - 2⁶ = 21673387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21673459) 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, 99311 + ... + 99528.

It is an arithmetic number, because the mean of its divisors is an integer number (5468100).

Almost surely, 2^21673451 is an apocalyptic number.

21673451 is a deficient number, since it is larger than the sum of its proper divisors (198949).

21673451 is a wasteful number, since it uses less digits than its factorization.

21673451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198948.

The product of its digits is 5040, while the sum is 29.

The square root of 21673451 is about 4655.4753785194. The cubic root of 21673451 is about 278.8106481884.

The spelling of 21673451 in words is "twenty-one million, six hundred seventy-three thousand, four hundred fifty-one".