21036424 has 16 divisors (see below), whose sum is σ = 40509900. Its totient is φ = 10233792.

The previous prime is 21036413. The next prime is 21036443. The reversal of 21036424 is 42463012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20520900 + 515524 = 4530^2 + 718^2 .

It is a super-2 number, since 2×21036424² = 885062269415552, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21036395 and 21036404.

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, 35239 + ... + 35830.

Almost surely, 2^21036424 is an apocalyptic number.

It is an amenable number.

21036424 is a deficient number, since it is larger than the sum of its proper divisors (19473476).

21036424 is a wasteful number, since it uses less digits than its factorization.

21036424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71112 (or 71108 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21036424 is about 4586.5481573837. The cubic root of 21036424 is about 276.0518351148.

Adding to 21036424 its reverse (42463012), we get a palindrome (63499436).

The spelling of 21036424 in words is "twenty-one million, thirty-six thousand, four hundred twenty-four".