21248775 has 18 divisors (see below), whose sum is σ = 38059320. Its totient is φ = 11332560.

The previous prime is 21248771. The next prime is 21248779. The reversal of 21248775 is 57784212.

It is an interprime number because it is at equal distance from previous prime (21248771) and next prime (21248779).

It is not a de Polignac number, because 21248775 - 2² = 21248771 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21248771) 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 17 ways as a sum of consecutive naturals, for example, 46995 + ... + 47444.

Almost surely, 2^21248775 is an apocalyptic number.

21248775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21248775 is a deficient number, since it is larger than the sum of its proper divisors (16810545).

21248775 is a wasteful number, since it uses less digits than its factorization.

21248775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94455 (or 94447 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 21248775 is about 4609.6393568261. The cubic root of 21248775 is about 276.9775903187.

The spelling of 21248775 in words is "twenty-one million, two hundred forty-eight thousand, seven hundred seventy-five".