21276645 has 16 divisors (see below), whose sum is σ = 36661632. Its totient is φ = 10474560.

The previous prime is 21276643. The next prime is 21276649. The reversal of 21276645 is 54667212.

It is not a de Polignac number, because 21276645 - 2¹ = 21276643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21276643) 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 15 ways as a sum of consecutive naturals, for example, 54361 + ... + 54750.

It is an arithmetic number, because the mean of its divisors is an integer number (2291352).

Almost surely, 2^21276645 is an apocalyptic number.

It is an amenable number.

21276645 is a deficient number, since it is larger than the sum of its proper divisors (15384987).

21276645 is a wasteful number, since it uses less digits than its factorization.

21276645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109132.

The product of its digits is 20160, while the sum is 33.

The square root of 21276645 is about 4612.6613792907. The cubic root of 21276645 is about 277.0986324804.

The spelling of 21276645 in words is "twenty-one million, two hundred seventy-six thousand, six hundred forty-five".