21272755 has 16 divisors (see below), whose sum is σ = 29297664. Its totient is φ = 14525280.

The previous prime is 21272731. The next prime is 21272759. The reversal of 21272755 is 55727212.

It is not a de Polignac number, because 21272755 - 2¹¹ = 21270707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21272759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8050 + ... + 10360.

It is an arithmetic number, because the mean of its divisors is an integer number (1831104).

Almost surely, 2^21272755 is an apocalyptic number.

21272755 is a deficient number, since it is larger than the sum of its proper divisors (8024909).

21272755 is a wasteful number, since it uses less digits than its factorization.

21272755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2586.

The product of its digits is 9800, while the sum is 31.

The square root of 21272755 is about 4612.2396945519. The cubic root of 21272755 is about 277.0817441759.

Adding to 21272755 its reverse (55727212), we get a palindrome (76999967).

The spelling of 21272755 in words is "twenty-one million, two hundred seventy-two thousand, seven hundred fifty-five".