21045515245 has 16 divisors (see below), whose sum is σ = 26765313840. Its totient is φ = 15831143424.

The previous prime is 21045515203. The next prime is 21045515251. The reversal of 21045515245 is 54251554012.

It can be written as a sum of positive squares in 8 ways, for example, as 14424804 + 21031090441 = 3798^2 + 145021^2 .

It is a cyclic number.

It is not a de Polignac number, because 21045515245 - 2¹⁵ = 21045482477 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21045515245.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24942 + ... + 206671.

It is an arithmetic number, because the mean of its divisors is an integer number (1672832115).

Almost surely, 2^21045515245 is an apocalyptic number.

It is an amenable number.

21045515245 is a deficient number, since it is larger than the sum of its proper divisors (5719798595).

21045515245 is a wasteful number, since it uses less digits than its factorization.

21045515245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232704.

The product of its (nonzero) digits is 40000, while the sum is 34.

The spelling of 21045515245 in words is "twenty-one billion, forty-five million, five hundred fifteen thousand, two hundred forty-five".