21535404 has 24 divisors (see below), whose sum is σ = 54817728. Its totient is φ = 6525840.

The previous prime is 21535403. The next prime is 21535411. The reversal of 21535404 is 40453512.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (21535403) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 81442 + ... + 81705.

It is an arithmetic number, because the mean of its divisors is an integer number (2284072).

Almost surely, 2^21535404 is an apocalyptic number.

It is an amenable number.

21535404 is an abundant number, since it is smaller than the sum of its proper divisors (33282324).

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

21535404 is a wasteful number, since it uses less digits than its factorization.

21535404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163165 (or 163163 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 21535404 is about 4640.6253888889. The cubic root of 21535404 is about 278.2174342260.

Adding to 21535404 its reverse (40453512), we get a palindrome (61988916).

It can be divided in two parts, 2153 and 5404, that added together give a palindrome (7557).

The spelling of 21535404 in words is "twenty-one million, five hundred thirty-five thousand, four hundred four".