21248447 has 12 divisors (see below), whose sum is σ = 23713368. Its totient is φ = 19021200.

The previous prime is 21248431. The next prime is 21248473. The reversal of 21248447 is 74484212.

It is not a de Polignac number, because 21248447 - 2⁴ = 21248431 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 (21248417) 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, 6797 + ... + 9417.

It is an arithmetic number, because the mean of its divisors is an integer number (1976114).

Almost surely, 2^21248447 is an apocalyptic number.

21248447 is a deficient number, since it is larger than the sum of its proper divisors (2464921).

21248447 is a wasteful number, since it uses less digits than its factorization.

21248447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2710 (or 2699 counting only the distinct ones).

The product of its digits is 14336, while the sum is 32.

The square root of 21248447 is about 4609.6037790682. The cubic root of 21248447 is about 276.9761651523.

The spelling of 21248447 in words is "twenty-one million, two hundred forty-eight thousand, four hundred forty-seven".