21481305 has 24 divisors (see below), whose sum is σ = 36283392. Its totient is φ = 10850976.

The previous prime is 21481301. The next prime is 21481309. The reversal of 21481305 is 50318412.

It is an interprime number because it is at equal distance from previous prime (21481301) and next prime (21481309).

It is not a de Polignac number, because 21481305 - 2² = 21481301 is a prime.

It is a super-2 number, since 2×21481305² = 922892929006050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21481301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3432 + ... + 7398.

It is an arithmetic number, because the mean of its divisors is an integer number (1511808).

Almost surely, 2^21481305 is an apocalyptic number.

It is an amenable number.

21481305 is a deficient number, since it is larger than the sum of its proper divisors (14802087).

21481305 is a wasteful number, since it uses less digits than its factorization.

21481305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4013 (or 3994 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21481305 is about 4634.7928756310. The cubic root of 21481305 is about 277.9842692477.

Adding to 21481305 its reverse (50318412), we get a palindrome (71799717).

The spelling of 21481305 in words is "twenty-one million, four hundred eighty-one thousand, three hundred five".