21265545 has 16 divisors (see below), whose sum is σ = 38885760. Its totient is φ = 9721344.

The previous prime is 21265537. The next prime is 21265549. The reversal of 21265545 is 54556212.

It is not a de Polignac number, because 21265545 - 2³ = 21265537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21265549) 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, 101160 + ... + 101369.

It is an arithmetic number, because the mean of its divisors is an integer number (2430360).

Almost surely, 2^21265545 is an apocalyptic number.

It is an amenable number.

21265545 is a deficient number, since it is larger than the sum of its proper divisors (17620215).

21265545 is a wasteful number, since it uses less digits than its factorization.

21265545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202544.

The product of its digits is 12000, while the sum is 30.

The square root of 21265545 is about 4611.4580123861. The cubic root of 21265545 is about 277.0504367576.

The spelling of 21265545 in words is "twenty-one million, two hundred sixty-five thousand, five hundred forty-five".