21092045 has 24 divisors (see below), whose sum is σ = 27779400. Its totient is φ = 15365376.

The previous prime is 21092017. The next prime is 21092047. The reversal of 21092045 is 54029012.

It can be written as a sum of positive squares in 12 ways, for example, as 4721929 + 16370116 = 2173^2 + 4046^2 .

It is not a de Polignac number, because 21092045 - 2⁶ = 21091981 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21092045.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21092047) 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 23 ways as a sum of consecutive naturals, for example, 91991 + ... + 92219.

It is an arithmetic number, because the mean of its divisors is an integer number (1157475).

Almost surely, 2^21092045 is an apocalyptic number.

It is an amenable number.

21092045 is a deficient number, since it is larger than the sum of its proper divisors (6687355).

21092045 is a wasteful number, since it uses less digits than its factorization.

21092045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21092045 is about 4592.6076470781. The cubic root of 21092045 is about 276.2949177249.

The spelling of 21092045 in words is "twenty-one million, ninety-two thousand, forty-five".