21299984 has 10 divisors (see below), whose sum is σ = 41268750. Its totient is φ = 10649984.

The previous prime is 21299983. The next prime is 21299987. The reversal of 21299984 is 48999212.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 1763584 = 4420^2 + 1328^2 .

It is not an unprimeable number, because it can be changed into a prime (21299983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665609 + ... + 665640.

It is an arithmetic number, because the mean of its divisors is an integer number (4126875).

Almost surely, 2^21299984 is an apocalyptic number.

It is an amenable number.

21299984 is a deficient number, since it is larger than the sum of its proper divisors (19968766).

21299984 is a wasteful number, since it uses less digits than its factorization.

21299984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331257 (or 1331251 counting only the distinct ones).

The product of its digits is 93312, while the sum is 44.

The square root of 21299984 is about 4615.1905702798. The cubic root of 21299984 is about 277.1999147664.

The spelling of 21299984 in words is "twenty-one million, two hundred ninety-nine thousand, nine hundred eighty-four".