21005650045 has 16 divisors (see below), whose sum is σ = 25352744112. Its totient is φ = 16707317760.

The previous prime is 21005650037. The next prime is 21005650049. The reversal of 21005650045 is 54005650012.

It can be written as a sum of positive squares in 8 ways, for example, as 1108290681 + 19897359364 = 33291^2 + 141058^2 .

It is not a de Polignac number, because 21005650045 - 2³ = 21005650037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21005649995 and 21005650022.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21005650049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1859715 + ... + 1870975.

It is an arithmetic number, because the mean of its divisors is an integer number (1584546507).

Almost surely, 2^21005650045 is an apocalyptic number.

It is an amenable number.

21005650045 is a deficient number, since it is larger than the sum of its proper divisors (4347094067).

21005650045 is a wasteful number, since it uses less digits than its factorization.

21005650045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13392.

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 21005650045 in words is "twenty-one billion, five million, six hundred fifty thousand, forty-five".