21443791 has 8 divisors (see below), whose sum is σ = 21697200. Its totient is φ = 21192192.

The previous prime is 21443777. The next prime is 21443801. The reversal of 21443791 is 19734412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21443791 - 2¹⁵ = 21411023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47535 + ... + 47983.

It is an arithmetic number, because the mean of its divisors is an integer number (2712150).

Almost surely, 2^21443791 is an apocalyptic number.

21443791 is a deficient number, since it is larger than the sum of its proper divisors (253409).

21443791 is a wasteful number, since it uses less digits than its factorization.

21443791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 905.

The product of its digits is 6048, while the sum is 31.

The square root of 21443791 is about 4630.7441086720. The cubic root of 21443791 is about 277.8223551511.

The spelling of 21443791 in words is "twenty-one million, four hundred forty-three thousand, seven hundred ninety-one".