21404052 has 36 divisors (see below), whose sum is σ = 54264756. Its totient is φ = 7113600.

The previous prime is 21404029. The next prime is 21404063. The reversal of 21404052 is 25040412.

It can be written as a sum of positive squares in 2 ways, for example, as 7160976 + 14243076 = 2676^2 + 3774^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 15802 + ... + 17102.

Almost surely, 2^21404052 is an apocalyptic number.

It is an amenable number.

21404052 is an abundant number, since it is smaller than the sum of its proper divisors (32860704).

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

21404052 is a wasteful number, since it uses less digits than its factorization.

21404052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768 (or 1763 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21404052 is about 4626.4513398500. The cubic root of 21404052 is about 277.6506316360.

Adding to 21404052 its reverse (25040412), we get a palindrome (46444464).

The spelling of 21404052 in words is "twenty-one million, four hundred four thousand, fifty-two".