21281061 has 8 divisors (see below), whose sum is σ = 28397664. Its totient is φ = 14175920.

The previous prime is 21281053. The next prime is 21281069. The reversal of 21281061 is 16018212.

It is an interprime number because it is at equal distance from previous prime (21281053) and next prime (21281069).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21281061 - 2³ = 21281053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21281069) 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 7 ways as a sum of consecutive naturals, for example, 3475 + ... + 7391.

It is an arithmetic number, because the mean of its divisors is an integer number (3549708).

Almost surely, 2^21281061 is an apocalyptic number.

It is an amenable number.

21281061 is a deficient number, since it is larger than the sum of its proper divisors (7116603).

21281061 is a wasteful number, since it uses less digits than its factorization.

21281061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5731.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21281061 is about 4613.1400368946. The cubic root of 21281061 is about 277.1178019017.

Adding to 21281061 its reverse (16018212), we get a palindrome (37299273).

The spelling of 21281061 in words is "twenty-one million, two hundred eighty-one thousand, sixty-one".