21248541 has 8 divisors (see below), whose sum is σ = 31479360. Its totient is φ = 14165676.

The previous prime is 21248533. The next prime is 21248543. The reversal of 21248541 is 14584212.

It is not a de Polignac number, because 21248541 - 2³ = 21248533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 786983 = 21248541 / (2 + 1 + 2 + 4 + 8 + 5 + 4 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21248543) 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 7 ways as a sum of consecutive naturals, for example, 393465 + ... + 393518.

It is an arithmetic number, because the mean of its divisors is an integer number (3934920).

Almost surely, 2^21248541 is an apocalyptic number.

It is an amenable number.

21248541 is a deficient number, since it is larger than the sum of its proper divisors (10230819).

21248541 is an equidigital number, since it uses as much as digits as its factorization.

21248541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786992 (or 786986 counting only the distinct ones).

The product of its digits is 2560, while the sum is 27.

The square root of 21248541 is about 4609.6139751610. The cubic root of 21248541 is about 276.9765735857.

The spelling of 21248541 in words is "twenty-one million, two hundred forty-eight thousand, five hundred forty-one".