21761275 has 12 divisors (see below), whose sum is σ = 28571832. Its totient is φ = 16384640.

The previous prime is 21761249. The next prime is 21761279. The reversal of 21761275 is 57216712.

It is not a de Polignac number, because 21761275 - 2⁹ = 21760763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21761279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25177 + ... + 26026.

It is an arithmetic number, because the mean of its divisors is an integer number (2380986).

Almost surely, 2^21761275 is an apocalyptic number.

21761275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21761275 is a deficient number, since it is larger than the sum of its proper divisors (6810557).

21761275 is a wasteful number, since it uses less digits than its factorization.

21761275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51230 (or 51225 counting only the distinct ones).

The product of its digits is 5880, while the sum is 31.

The square root of 21761275 is about 4664.8981768094. The cubic root of 21761275 is about 279.1867345293.

Adding to 21761275 its reverse (57216712), we get a palindrome (78977987).

The spelling of 21761275 in words is "twenty-one million, seven hundred sixty-one thousand, two hundred seventy-five".