21355105 has 16 divisors (see below), whose sum is σ = 26634960. Its totient is φ = 16422912.

The previous prime is 21355097. The next prime is 21355121. The reversal of 21355105 is 50155312.

It can be written as a sum of positive squares in 8 ways, for example, as 2588881 + 18766224 = 1609^2 + 4332^2 .

It is a cyclic number.

It is not a de Polignac number, because 21355105 - 2³ = 21355097 is a prime.

It is a super-2 number, since 2×21355105² = 912081019122050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15817 + ... + 17113.

It is an arithmetic number, because the mean of its divisors is an integer number (1664685).

Almost surely, 2^21355105 is an apocalyptic number.

It is an amenable number.

21355105 is a deficient number, since it is larger than the sum of its proper divisors (5279855).

21355105 is a wasteful number, since it uses less digits than its factorization.

21355105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428.

The product of its (nonzero) digits is 750, while the sum is 22.

The square root of 21355105 is about 4621.1584045562. The cubic root of 21355105 is about 277.4388253539.

The spelling of 21355105 in words is "twenty-one million, three hundred fifty-five thousand, one hundred five".