21321436 has 6 divisors (see below), whose sum is σ = 37312520. Its totient is φ = 10660716.

The previous prime is 21321431. The next prime is 21321449. The reversal of 21321436 is 63412312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2665176 + ... + 2665183.

Almost surely, 2^21321436 is an apocalyptic number.

It is an amenable number.

21321436 is a deficient number, since it is larger than the sum of its proper divisors (15991084).

21321436 is a wasteful number, since it uses less digits than its factorization.

21321436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5330363 (or 5330361 counting only the distinct ones).

The product of its digits is 864, while the sum is 22.

The square root of 21321436 is about 4617.5140497891. The cubic root of 21321436 is about 277.2929429643.

Adding to 21321436 its reverse (63412312), we get a palindrome (84733748).

The spelling of 21321436 in words is "twenty-one million, three hundred twenty-one thousand, four hundred thirty-six".