21447349 has 12 divisors (see below), whose sum is σ = 27217728. Its totient is φ = 16711800.

The previous prime is 21447341. The next prime is 21447359. The reversal of 21447349 is 94374412.

It is a happy number.

It is not a de Polignac number, because 21447349 - 2³ = 21447341 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 (21447341) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19357 + ... + 20434.

It is an arithmetic number, because the mean of its divisors is an integer number (2268144).

Almost surely, 2^21447349 is an apocalyptic number.

It is an amenable number.

21447349 is a deficient number, since it is larger than the sum of its proper divisors (5770379).

21447349 is a wasteful number, since it uses less digits than its factorization.

21447349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39816 (or 39809 counting only the distinct ones).

The product of its digits is 24192, while the sum is 34.

The square root of 21447349 is about 4631.1282642570. The cubic root of 21447349 is about 277.8377199292.

The spelling of 21447349 in words is "twenty-one million, four hundred forty-seven thousand, three hundred forty-nine".