13505611645 has 4 divisors (see below), whose sum is σ = 16206733980. Its totient is φ = 10804489312.

The previous prime is 13505611607. The next prime is 13505611649. The reversal of 13505611645 is 54611650531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54611650531 = 12437 ⋅4391063.

It can be written as a sum of positive squares in 2 ways, for example, as 8698546756 + 4807064889 = 93266^2 + 69333^2 .

It is a cyclic number.

It is not a de Polignac number, because 13505611645 - 2¹³ = 13505603453 is a prime.

It is a super-3 number, since 3×13505611645³ (a number of 31 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13505611649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1350561160 + ... + 1350561169.

It is an arithmetic number, because the mean of its divisors is an integer number (4051683495).

Almost surely, 2^13505611645 is an apocalyptic number.

It is an amenable number.

13505611645 is a deficient number, since it is larger than the sum of its proper divisors (2701122335).

13505611645 is an equidigital number, since it uses as much as digits as its factorization.

13505611645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2701122334.

The product of its (nonzero) digits is 54000, while the sum is 37.

The spelling of 13505611645 in words is "thirteen billion, five hundred five million, six hundred eleven thousand, six hundred forty-five".