21455105 has 32 divisors (see below), whose sum is σ = 31539456. Its totient is φ = 13676544.

The previous prime is 21455101. The next prime is 21455107. The reversal of 21455105 is 50155412.

It is a happy number.

It is not a de Polignac number, because 21455105 - 2² = 21455101 is a prime.

It is a super-2 number, since 2×21455105² = 920643061122050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21455101) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63497 + ... + 63833.

It is an arithmetic number, because the mean of its divisors is an integer number (985608).

Almost surely, 2^21455105 is an apocalyptic number.

It is an amenable number.

21455105 is a deficient number, since it is larger than the sum of its proper divisors (10084351).

21455105 is a wasteful number, since it uses less digits than its factorization.

21455105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 21455105 is about 4631.9655655024. The cubic root of 21455105 is about 277.8712073570.

The spelling of 21455105 in words is "twenty-one million, four hundred fifty-five thousand, one hundred five".