13881779 has 4 divisors (see below), whose sum is σ = 14177184. Its totient is φ = 13586376.

The previous prime is 13881773. The next prime is 13881781. The reversal of 13881779 is 97718831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97718831 = 7 ⋅13959833.

It is a cyclic number.

It is not a de Polignac number, because 13881779 - 2⁸ = 13881523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13881773) 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, 147632 + ... + 147725.

It is an arithmetic number, because the mean of its divisors is an integer number (3544296).

Almost surely, 2^13881779 is an apocalyptic number.

13881779 is a deficient number, since it is larger than the sum of its proper divisors (295405).

13881779 is an equidigital number, since it uses as much as digits as its factorization.

13881779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295404.

The product of its digits is 84672, while the sum is 44.

The square root of 13881779 is about 3725.8259486992. The cubic root of 13881779 is about 240.3339044468. Note that the first 3 decimals are identical.

The spelling of 13881779 in words is "thirteen million, eight hundred eighty-one thousand, seven hundred seventy-nine".