21481943 has 12 divisors (see below), whose sum is σ = 25402392. Its totient is φ = 18108720.

The previous prime is 21481939. The next prime is 21481949. The reversal of 21481943 is 34918412.

It is a happy number.

It is not a de Polignac number, because 21481943 - 2² = 21481939 is a prime.

It is a super-2 number, since 2×21481943² = 922947750110498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481949) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 605 + ... + 6582.

It is an arithmetic number, because the mean of its divisors is an integer number (2116866).

Almost surely, 2^21481943 is an apocalyptic number.

21481943 is a deficient number, since it is larger than the sum of its proper divisors (3920449).

21481943 is an equidigital number, since it uses as much as digits as its factorization.

21481943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7262 (or 7255 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 21481943 is about 4634.8617023596. The cubic root of 21481943 is about 277.9870212874.

The spelling of 21481943 in words is "twenty-one million, four hundred eighty-one thousand, nine hundred forty-three".