21447013 has 16 divisors (see below), whose sum is σ = 26659584. Its totient is φ = 16830720.

The previous prime is 21447011. The next prime is 21447043. The reversal of 21447013 is 31074412.

It is a cyclic number.

It is not a de Polignac number, because 21447013 - 2¹ = 21447011 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21447011) 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 15 ways as a sum of consecutive naturals, for example, 1968 + ... + 6838.

It is an arithmetic number, because the mean of its divisors is an integer number (1666224).

Almost surely, 2^21447013 is an apocalyptic number.

It is an amenable number.

21447013 is a deficient number, since it is larger than the sum of its proper divisors (5212571).

21447013 is a wasteful number, since it uses less digits than its factorization.

21447013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4932.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21447013 is about 4631.0919878577. The cubic root of 21447013 is about 277.8362690279.

The spelling of 21447013 in words is "twenty-one million, four hundred forty-seven thousand, thirteen".