21535460 has 12 divisors (see below), whose sum is σ = 45224508. Its totient is φ = 8614176.

The previous prime is 21535433. The next prime is 21535477. The reversal of 21535460 is 6453512.

It can be written as a sum of positive squares in 2 ways, for example, as 6666724 + 14868736 = 2582^2 + 3856^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 538367 + ... + 538406.

It is an arithmetic number, because the mean of its divisors is an integer number (3768709).

Almost surely, 2^21535460 is an apocalyptic number.

21535460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21535460 is an abundant number, since it is smaller than the sum of its proper divisors (23689048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21535460 is a wasteful number, since it uses less digits than its factorization.

21535460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076782 (or 1076780 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21535460 is about 4640.6314225545. The cubic root of 21535460 is about 278.2176753818.

Adding to 21535460 its reverse (6453512), we get a palindrome (27988972).

The spelling of 21535460 in words is "twenty-one million, five hundred thirty-five thousand, four hundred sixty".