21440755 has 16 divisors (see below), whose sum is σ = 29582784. Its totient is φ = 14613120.

The previous prime is 21440719. The next prime is 21440801. The reversal of 21440755 is 55704412.

It is not a de Polignac number, because 21440755 - 2¹⁷ = 21309683 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 4285 + ... + 7825.

It is an arithmetic number, because the mean of its divisors is an integer number (1848924).

Almost surely, 2^21440755 is an apocalyptic number.

21440755 is a deficient number, since it is larger than the sum of its proper divisors (8142029).

21440755 is a wasteful number, since it uses less digits than its factorization.

21440755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3726.

The product of its (nonzero) digits is 5600, while the sum is 28.

The square root of 21440755 is about 4630.4162879810. The cubic root of 21440755 is about 277.8092432208.

The spelling of 21440755 in words is "twenty-one million, four hundred forty thousand, seven hundred fifty-five".