13778144721 has 12 divisors (see below), whose sum is σ = 21711016080. Its totient is φ = 8350390680.

The previous prime is 13778144707. The next prime is 13778144741. The reversal of 13778144721 is 12744187731.

13778144721 is a `hidden beast` number, since 137 + 78 + 1 + 447 + 2 + 1 = 666.

It is not a de Polignac number, because 13778144721 - 2⁷ = 13778144593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13778144741) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69586491 + ... + 69586688.

It is an arithmetic number, because the mean of its divisors is an integer number (1809251340).

Almost surely, 2^13778144721 is an apocalyptic number.

13778144721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13778144721 is a deficient number, since it is larger than the sum of its proper divisors (7932871359).

13778144721 is a wasteful number, since it uses less digits than its factorization.

13778144721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139173196 (or 139173193 counting only the distinct ones).

The product of its digits is 263424, while the sum is 45.

The spelling of 13778144721 in words is "thirteen billion, seven hundred seventy-eight million, one hundred forty-four thousand, seven hundred twenty-one".