21105461 has 8 divisors (see below), whose sum is σ = 22814904. Its totient is φ = 19408320.

The previous prime is 21105457. The next prime is 21105473. The reversal of 21105461 is 16450112.

It can be written as a sum of positive squares in 4 ways, for example, as 625 + 21104836 = 25^2 + 4594^2 .

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 21105461 - 2² = 21105457 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 671 + ... + 6531.

It is an arithmetic number, because the mean of its divisors is an integer number (2851863).

Almost surely, 2^21105461 is an apocalyptic number.

It is an amenable number.

21105461 is a deficient number, since it is larger than the sum of its proper divisors (1709443).

21105461 is a wasteful number, since it uses less digits than its factorization.

21105461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6151.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21105461 is about 4594.0680230053. The cubic root of 21105461 is about 276.3534862037.

Adding to 21105461 its reverse (16450112), we get a palindrome (37555573).

The spelling of 21105461 in words is "twenty-one million, one hundred five thousand, four hundred sixty-one".