21306646145 has 16 divisors (see below), whose sum is σ = 25955506512. Its totient is φ = 16787635200.

The previous prime is 21306646139. The next prime is 21306646171. The reversal of 21306646145 is 54164660312.

It can be written as a sum of positive squares in 8 ways, for example, as 671898241 + 20634747904 = 25921^2 + 143648^2 .

It is not a de Polignac number, because 21306646145 - 2⁴ = 21306646129 is a prime.

It is a super-2 number, since 2×21306646145² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21306646099 and 21306646108.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 214229 + ... + 297501.

It is an arithmetic number, because the mean of its divisors is an integer number (1622219157).

Almost surely, 2^21306646145 is an apocalyptic number.

It is an amenable number.

21306646145 is a deficient number, since it is larger than the sum of its proper divisors (4648860367).

21306646145 is an equidigital number, since it uses as much as digits as its factorization.

21306646145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84052.

The product of its (nonzero) digits is 103680, while the sum is 38.

The spelling of 21306646145 in words is "twenty-one billion, three hundred six million, six hundred forty-six thousand, one hundred forty-five".