21754505 has 4 divisors (see below), whose sum is σ = 26105412. Its totient is φ = 17403600.

The previous prime is 21754489. The next prime is 21754507. The reversal of 21754505 is 50545712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7070281 + 14684224 = 2659^2 + 3832^2 .

It is not a de Polignac number, because 21754505 - 2⁴ = 21754489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21754507) 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 3 ways as a sum of consecutive naturals, for example, 2175446 + ... + 2175455.

It is an arithmetic number, because the mean of its divisors is an integer number (6526353).

Almost surely, 2^21754505 is an apocalyptic number.

It is an amenable number.

21754505 is a deficient number, since it is larger than the sum of its proper divisors (4350907).

21754505 is an equidigital number, since it uses as much as digits as its factorization.

21754505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4350906.

The product of its (nonzero) digits is 7000, while the sum is 29.

The square root of 21754505 is about 4664.1724882341. The cubic root of 21754505 is about 279.1577795740.

The spelling of 21754505 in words is "twenty-one million, seven hundred fifty-four thousand, five hundred five".