21450005 has 16 divisors (see below), whose sum is σ = 27365040. Its totient is φ = 16084992.

The previous prime is 21449959. The next prime is 21450019. The reversal of 21450005 is 50005412.

It can be written as a sum of positive squares in 8 ways, for example, as 3844 + 21446161 = 62^2 + 4631^2 .

It is not a de Polignac number, because 21450005 - 2⁶ = 21449941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

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, 34457 + ... + 35073.

It is an arithmetic number, because the mean of its divisors is an integer number (1710315).

Almost surely, 2^21450005 is an apocalyptic number.

It is an amenable number.

21450005 is a deficient number, since it is larger than the sum of its proper divisors (5915035).

21450005 is a wasteful number, since it uses less digits than its factorization.

21450005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1048.

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 21450005 is about 4631.4150105556. The cubic root of 21450005 is about 277.8491884255.

Adding to 21450005 its reverse (50005412), we get a palindrome (71455417).

The spelling of 21450005 in words is "twenty-one million, four hundred fifty thousand, five".