66917938 has 4 divisors (see below), whose sum is σ = 100376910. Its totient is φ = 33458968.

The previous prime is 66917927. The next prime is 66917947. The reversal of 66917938 is 83971966.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 65076489 + 1841449 = 8067^2 + 1357^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 66917891 and 66917900.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16729483 + ... + 16729486.

Almost surely, 2^66917938 is an apocalyptic number.

66917938 is a deficient number, since it is larger than the sum of its proper divisors (33458972).

66917938 is a wasteful number, since it uses less digits than its factorization.

66917938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33458971.

The product of its digits is 489888, while the sum is 49.

The square root of 66917938 is about 8180.3385015536. The cubic root of 66917938 is about 405.9889220205.

The spelling of 66917938 in words is "sixty-six million, nine hundred seventeen thousand, nine hundred thirty-eight".