21263984 has 40 divisors (see below), whose sum is σ = 47303520. Its totient is φ = 9070848.

The previous prime is 21263959. The next prime is 21263987. The reversal of 21263984 is 48936212.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21263987) 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, 41522 + ... + 42030.

It is an arithmetic number, because the mean of its divisors is an integer number (1182588).

Almost surely, 2^21263984 is an apocalyptic number.

It is an amenable number.

21263984 is an abundant number, since it is smaller than the sum of its proper divisors (26039536).

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

21263984 is a wasteful number, since it uses less digits than its factorization.

21263984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897 (or 891 counting only the distinct ones).

The product of its digits is 20736, while the sum is 35.

The square root of 21263984 is about 4611.2887569529. The cubic root of 21263984 is about 277.0436576177.

The spelling of 21263984 in words is "twenty-one million, two hundred sixty-three thousand, nine hundred eighty-four".