21027755 has 16 divisors (see below), whose sum is σ = 29833920. Its totient is φ = 13921152.

The previous prime is 21027709. The next prime is 21027767. The reversal of 21027755 is 55772012.

It is not a de Polignac number, because 21027755 - 2⁸ = 21027499 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

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, 9344 + ... + 11373.

It is an arithmetic number, because the mean of its divisors is an integer number (1864620).

Almost surely, 2^21027755 is an apocalyptic number.

21027755 is a deficient number, since it is larger than the sum of its proper divisors (8806165).

21027755 is a wasteful number, since it uses less digits than its factorization.

21027755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20758.

The product of its (nonzero) digits is 4900, while the sum is 29.

The square root of 21027755 is about 4585.6030137813. The cubic root of 21027755 is about 276.0139100670.

Adding to 21027755 its reverse (55772012), we get a palindrome (76799767).

The spelling of 21027755 in words is "twenty-one million, twenty-seven thousand, seven hundred fifty-five".