21747105 has 24 divisors (see below), whose sum is σ = 38338560. Its totient is φ = 11400480.

The previous prime is 21747101. The next prime is 21747107. The reversal of 21747105 is 50174712.

It is not a de Polignac number, because 21747105 - 2² = 21747101 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21747101) 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 23 ways as a sum of consecutive naturals, for example, 1441 + ... + 6750.

It is an arithmetic number, because the mean of its divisors is an integer number (1597440).

Almost surely, 2^21747105 is an apocalyptic number.

It is an amenable number.

21747105 is a deficient number, since it is larger than the sum of its proper divisors (16591455).

21747105 is a wasteful number, since it uses less digits than its factorization.

21747105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8261 (or 8258 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21747105 is about 4663.3791396368. The cubic root of 21747105 is about 279.1261232674.

The spelling of 21747105 in words is "twenty-one million, seven hundred forty-seven thousand, one hundred five".