13643721806 has 32 divisors (see below), whose sum is σ = 24693324768. Its totient is φ = 5569914240.

The previous prime is 13643721803. The next prime is 13643721821. The reversal of 13643721806 is 60812734631.

It is a super-2 number, since 2×13643721806² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13643721803) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 634085 + ... + 655248.

It is an arithmetic number, because the mean of its divisors is an integer number (771666399).

Almost surely, 2^13643721806 is an apocalyptic number.

13643721806 is a deficient number, since it is larger than the sum of its proper divisors (11049602962).

13643721806 is a wasteful number, since it uses less digits than its factorization.

13643721806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1289396.

The product of its (nonzero) digits is 145152, while the sum is 41.

The spelling of 13643721806 in words is "thirteen billion, six hundred forty-three million, seven hundred twenty-one thousand, eight hundred six".