21702105 has 24 divisors (see below), whose sum is σ = 37739520. Its totient is φ = 11536800.

The previous prime is 21702103. The next prime is 21702157. The reversal of 21702105 is 50120712.

It is not a de Polignac number, because 21702105 - 2¹ = 21702103 is a prime.

It is a super-2 number, since 2×21702105² = 941962722862050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21702103) 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, 18280 + ... + 19430.

It is an arithmetic number, because the mean of its divisors is an integer number (1572480).

Almost surely, 2^21702105 is an apocalyptic number.

It is an amenable number.

21702105 is a deficient number, since it is larger than the sum of its proper divisors (16037415).

21702105 is a wasteful number, since it uses less digits than its factorization.

21702105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581 (or 1578 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21702105 is about 4658.5518136004. The cubic root of 21702105 is about 278.9334639194.

Adding to 21702105 its reverse (50120712), we get a palindrome (71822817).

The spelling of 21702105 in words is "twenty-one million, seven hundred two thousand, one hundred five".