21924691 has 4 divisors (see below), whose sum is σ = 22023232. Its totient is φ = 21826152.

The previous prime is 21924653. The next prime is 21924697. The reversal of 21924691 is 19642912.

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 21924691 - 2⁹ = 21924179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21924697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48936 + ... + 49381.

It is an arithmetic number, because the mean of its divisors is an integer number (5505808).

Almost surely, 2^21924691 is an apocalyptic number.

21924691 is a deficient number, since it is larger than the sum of its proper divisors (98541).

21924691 is an equidigital number, since it uses as much as digits as its factorization.

21924691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98540.

The product of its digits is 7776, while the sum is 34.

The square root of 21924691 is about 4682.3809114595. The cubic root of 21924691 is about 279.8838421247.

The spelling of 21924691 in words is "twenty-one million, nine hundred twenty-four thousand, six hundred ninety-one".