21148547 has 6 divisors (see below), whose sum is σ = 24601428. Its totient is φ = 18127284.

The previous prime is 21148529. The next prime is 21148549. The reversal of 21148547 is 74584112.

It is a happy number.

It is not a de Polignac number, because 21148547 - 2¹⁰ = 21147523 is a prime.

It is a super-2 number, since 2×21148547² = 894522080422418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21148549) 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 5 ways as a sum of consecutive naturals, for example, 215753 + ... + 215850.

It is an arithmetic number, because the mean of its divisors is an integer number (4100238).

Almost surely, 2^21148547 is an apocalyptic number.

21148547 is a deficient number, since it is larger than the sum of its proper divisors (3452881).

21148547 is an equidigital number, since it uses as much as digits as its factorization.

21148547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431617 (or 431610 counting only the distinct ones).

The product of its digits is 8960, while the sum is 32.

The square root of 21148547 is about 4598.7549401985. The cubic root of 21148547 is about 276.5414134412.

The spelling of 21148547 in words is "twenty-one million, one hundred forty-eight thousand, five hundred forty-seven".