13778666 has 16 divisors (see below), whose sum is σ = 22603968. Its totient is φ = 6247200.

The previous prime is 13778659. The next prime is 13778671. The reversal of 13778666 is 66687731.

It is a happy number.

It is a super-3 number, since 3×13778666³ (a number of 22 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16331 + ... + 17153.

It is an arithmetic number, because the mean of its divisors is an integer number (1412748).

Almost surely, 2^13778666 is an apocalyptic number.

13778666 is a deficient number, since it is larger than the sum of its proper divisors (8825302).

13778666 is a wasteful number, since it uses less digits than its factorization.

13778666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1597.

The product of its digits is 254016, while the sum is 44.

The square root of 13778666 is about 3711.9625536904. The cubic root of 13778666 is about 239.7373631590.

The spelling of 13778666 in words is "thirteen million, seven hundred seventy-eight thousand, six hundred sixty-six".