21294881145 has 24 divisors (see below), whose sum is σ = 37811401992. Its totient is φ = 11080262400.

The previous prime is 21294881143. The next prime is 21294881159. The reversal of 21294881145 is 54118849212.

21294881145 is a `hidden beast` number, since 2 + 1 + 29 + 488 + 1 + 145 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 23242041 + 21271639104 = 4821^2 + 145848^2 .

It is not a de Polignac number, because 21294881145 - 2¹ = 21294881143 is a prime.

It is a super-2 number, since 2×21294881145² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21294881145.

It is not an unprimeable number, because it can be changed into a prime (21294881143) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5769126 + ... + 5772815.

It is an arithmetic number, because the mean of its divisors is an integer number (1575475083).

Almost surely, 2^21294881145 is an apocalyptic number.

It is an amenable number.

21294881145 is a deficient number, since it is larger than the sum of its proper divisors (16516520847).

21294881145 is a wasteful number, since it uses less digits than its factorization.

21294881145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11541993 (or 11541990 counting only the distinct ones).

The product of its digits is 184320, while the sum is 45.

The spelling of 21294881145 in words is "twenty-one billion, two hundred ninety-four million, eight hundred eighty-one thousand, one hundred forty-five".