21481965 has 24 divisors (see below), whose sum is σ = 39427128. Its totient is φ = 10782720.

The previous prime is 21481963. The next prime is 21482029. The reversal of 21481965 is 56918412.

It can be written as a sum of positive squares in 4 ways, for example, as 2350089 + 19131876 = 1533^2 + 4374^2 .

It is not a de Polignac number, because 21481965 - 2¹ = 21481963 is a prime.

It is a super-2 number, since 2×21481965² = 922949640522450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481963) 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, 13276 + ... + 14805.

It is an arithmetic number, because the mean of its divisors is an integer number (1642797).

Almost surely, 2^21481965 is an apocalyptic number.

It is an amenable number.

21481965 is a deficient number, since it is larger than the sum of its proper divisors (17945163).

21481965 is a wasteful number, since it uses less digits than its factorization.

21481965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28109 (or 28106 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21481965 is about 4634.8640756769. The cubic root of 21481965 is about 277.9871161843.

The spelling of 21481965 in words is "twenty-one million, four hundred eighty-one thousand, nine hundred sixty-five".