66727778 has 16 divisors (see below), whose sum is σ = 109560696. Its totient is φ = 30291840.

The previous prime is 66727769. The next prime is 66727781. The reversal of 66727778 is 87772766.

It can be written as a sum of positive squares in 4 ways, for example, as 8922169 + 57805609 = 2987^2 + 7603^2 .

It is a Curzon number.

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, 19451 + ... + 22622.

Almost surely, 2^66727778 is an apocalyptic number.

66727778 is a deficient number, since it is larger than the sum of its proper divisors (42832918).

66727778 is a wasteful number, since it uses less digits than its factorization.

66727778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42149.

The product of its digits is 1382976, while the sum is 50.

The square root of 66727778 is about 8168.7072416632. The cubic root of 66727778 is about 405.6039923577.

The spelling of 66727778 in words is "sixty-six million, seven hundred twenty-seven thousand, seven hundred seventy-eight".