21272878 has 16 divisors (see below), whose sum is σ = 35303040. Its totient is φ = 9532600.

The previous prime is 21272843. The next prime is 21272947. The reversal of 21272878 is 87827212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5248 + ... + 8371.

It is an arithmetic number, because the mean of its divisors is an integer number (2206440).

Almost surely, 2^21272878 is an apocalyptic number.

21272878 is a deficient number, since it is larger than the sum of its proper divisors (14030162).

21272878 is a wasteful number, since it uses less digits than its factorization.

21272878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13703.

The product of its digits is 25088, while the sum is 37.

The square root of 21272878 is about 4612.2530286184. The cubic root of 21272878 is about 277.0822782078.

It can be divided in two parts, 2127 and 2878, that added together give a palindrome (5005).

The spelling of 21272878 in words is "twenty-one million, two hundred seventy-two thousand, eight hundred seventy-eight".