21361924 has 6 divisors (see below), whose sum is σ = 37383374. Its totient is φ = 10680960.

The previous prime is 21361919. The next prime is 21361931. The reversal of 21361924 is 42916312.

It can be written as a sum of positive squares in only one way, i.e., 15745024 + 5616900 = 3968^2 + 2370^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21361892 and 21361901.

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 as a sum of consecutive naturals, namely, 2670237 + ... + 2670244.

Almost surely, 2^21361924 is an apocalyptic number.

It is an amenable number.

21361924 is a deficient number, since it is larger than the sum of its proper divisors (16021450).

21361924 is a wasteful number, since it uses less digits than its factorization.

21361924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5340485 (or 5340483 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

The square root of 21361924 is about 4621.8961476866. The cubic root of 21361924 is about 277.4683523143.

The spelling of 21361924 in words is "twenty-one million, three hundred sixty-one thousand, nine hundred twenty-four".