13644643551 has 64 divisors (see below), whose sum is σ = 22903136256. Its totient is φ = 7019395200.

The previous prime is 13644643543. The next prime is 13644643567. The reversal of 13644643551 is 15534644631.

It is a happy number.

It is not a de Polignac number, because 13644643551 - 2³ = 13644643543 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13644643511) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12835446 + ... + 12836508.

It is an arithmetic number, because the mean of its divisors is an integer number (357861504).

Almost surely, 2^13644643551 is an apocalyptic number.

13644643551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

13644643551 is a deficient number, since it is larger than the sum of its proper divisors (9258492705).

13644643551 is a wasteful number, since it uses less digits than its factorization.

13644643551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1572.

The product of its digits is 518400, while the sum is 42.

The spelling of 13644643551 in words is "thirteen billion, six hundred forty-four million, six hundred forty-three thousand, five hundred fifty-one".