21482509 has 4 divisors (see below), whose sum is σ = 22746204. Its totient is φ = 20218816.

The previous prime is 21482491. The next prime is 21482519. The reversal of 21482509 is 90528412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7209225 + 14273284 = 2685^2 + 3778^2 .

It is a cyclic number.

It is not a de Polignac number, because 21482509 - 2¹⁵ = 21449741 is a prime.

It is a super-2 number, since 2×21482509² = 922996385870162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21482519) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 631822 + ... + 631855.

It is an arithmetic number, because the mean of its divisors is an integer number (5686551).

Almost surely, 2^21482509 is an apocalyptic number.

It is an amenable number.

21482509 is a deficient number, since it is larger than the sum of its proper divisors (1263695).

21482509 is a wasteful number, since it uses less digits than its factorization.

21482509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1263694.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 21482509 is about 4634.9227609530. The cubic root of 21482509 is about 277.9894627064.

The spelling of 21482509 in words is "twenty-one million, four hundred eighty-two thousand, five hundred nine".