21960281 has 6 divisors (see below), whose sum is σ = 25545690. Its totient is φ = 18823056.

The previous prime is 21960271. The next prime is 21960287. The reversal of 21960281 is 18206912.

It can be written as a sum of positive squares in only one way, i.e., 19758025 + 2202256 = 4445^2 + 1484^2 .

It is not a de Polignac number, because 21960281 - 2²² = 17765977 is a prime.

It is a super-2 number, since 2×21960281² = 964507883197922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21960287) 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 5 ways as a sum of consecutive naturals, for example, 224036 + ... + 224133.

It is an arithmetic number, because the mean of its divisors is an integer number (4257615).

Almost surely, 2^21960281 is an apocalyptic number.

It is an amenable number.

21960281 is a deficient number, since it is larger than the sum of its proper divisors (3585409).

21960281 is an equidigital number, since it uses as much as digits as its factorization.

21960281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448183 (or 448176 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21960281 is about 4686.1797874175. The cubic root of 21960281 is about 280.0352039070.

The spelling of 21960281 in words is "twenty-one million, nine hundred sixty thousand, two hundred eighty-one".