21146434065 has 24 divisors (see below), whose sum is σ = 37644465768. Its totient is φ = 10973283840.

The previous prime is 21146434039. The next prime is 21146434081. The reversal of 21146434065 is 56043464112.

21146434065 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 643 + 4 + 0 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 11653634304 + 9492799761 = 107952^2 + 97431^2 .

It is not a de Polignac number, because 21146434065 - 2⁸ = 21146433809 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6348616 + ... + 6351945.

It is an arithmetic number, because the mean of its divisors is an integer number (1568519407).

Almost surely, 2^21146434065 is an apocalyptic number.

It is an amenable number.

21146434065 is a deficient number, since it is larger than the sum of its proper divisors (16498031703).

21146434065 is a wasteful number, since it uses less digits than its factorization.

21146434065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12700609 (or 12700606 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

Adding to 21146434065 its reverse (56043464112), we get a palindrome (77189898177).

The spelling of 21146434065 in words is "twenty-one billion, one hundred forty-six million, four hundred thirty-four thousand, sixty-five".