21248361 has 12 divisors (see below), whose sum is σ = 31682560. Its totient is φ = 13708440.

The previous prime is 21248309. The next prime is 21248363. The reversal of 21248361 is 16384212.

It is a de Polignac number, because none of the positive numbers 2^k-21248361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21248363) 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 11 ways as a sum of consecutive naturals, for example, 37801 + ... + 38358.

Almost surely, 2^21248361 is an apocalyptic number.

It is an amenable number.

21248361 is a deficient number, since it is larger than the sum of its proper divisors (10434199).

21248361 is a wasteful number, since it uses less digits than its factorization.

21248361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76196 (or 76193 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21248361 is about 4609.5944507082. The cubic root of 21248361 is about 276.9757914783.

It can be divided in two parts, 21248 and 361, that added together give a square (21609 = 147²).

The spelling of 21248361 in words is "twenty-one million, two hundred forty-eight thousand, three hundred sixty-one".