21369447 has 48 divisors (see below), whose sum is σ = 36090880. Its totient is φ = 12474000.

The previous prime is 21369407. The next prime is 21369451. The reversal of 21369447 is 74496312.

It is not a de Polignac number, because 21369447 - 2¹⁴ = 21353063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21369407) 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 47 ways as a sum of consecutive naturals, for example, 101172 + ... + 101382.

Almost surely, 2^21369447 is an apocalyptic number.

21369447 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21369447 is a deficient number, since it is larger than the sum of its proper divisors (14721433).

21369447 is a wasteful number, since it uses less digits than its factorization.

21369447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273 (or 256 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 21369447 is about 4622.7099195169. The cubic root of 21369447 is about 277.5009203768.

The spelling of 21369447 in words is "twenty-one million, three hundred sixty-nine thousand, four hundred forty-seven".