21929673 has 4 divisors (see below), whose sum is σ = 29239568. Its totient is φ = 14619780.

The previous prime is 21929669. The next prime is 21929681. The reversal of 21929673 is 37692912.

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 not a de Polignac number, because 21929673 - 2² = 21929669 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21929623) 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, 3654943 + ... + 3654948.

It is an arithmetic number, because the mean of its divisors is an integer number (7309892).

Almost surely, 2^21929673 is an apocalyptic number.

It is an amenable number.

21929673 is a deficient number, since it is larger than the sum of its proper divisors (7309895).

21929673 is an equidigital number, since it uses as much as digits as its factorization.

21929673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7309894.

The product of its digits is 40824, while the sum is 39.

The square root of 21929673 is about 4682.9128755509. The cubic root of 21929673 is about 279.9050400776.

It can be divided in two parts, 219 and 29673, that added together give a palindrome (29892).

The spelling of 21929673 in words is "twenty-one million, nine hundred twenty-nine thousand, six hundred seventy-three".