21445305 has 32 divisors (see below), whose sum is σ = 39481344. Its totient is φ = 9736896.

The previous prime is 21445247. The next prime is 21445327. The reversal of 21445305 is 50354412.

It is not a de Polignac number, because 21445305 - 2¹³ = 21437113 is a prime.

It is a super-2 number, since 2×21445305² = 919802213086050, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16924 + ... + 18146.

It is an arithmetic number, because the mean of its divisors is an integer number (1233792).

Almost surely, 2^21445305 is an apocalyptic number.

It is an amenable number.

21445305 is a deficient number, since it is larger than the sum of its proper divisors (18036039).

21445305 is a wasteful number, since it uses less digits than its factorization.

21445305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1405.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 21445305 is about 4630.9075784343. The cubic root of 21445305 is about 277.8288933785.

Adding to 21445305 its reverse (50354412), we get a palindrome (71799717).

The spelling of 21445305 in words is "twenty-one million, four hundred forty-five thousand, three hundred five".