66197506 has 4 divisors (see below), whose sum is σ = 99296262. Its totient is φ = 33098752.

The previous prime is 66197449. The next prime is 66197543. The reversal of 66197506 is 60579166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60579166 = 2 ⋅30289583.

It can be written as a sum of positive squares in only one way, i.e., 48177481 + 18020025 = 6941^2 + 4245^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16549375 + ... + 16549378.

Almost surely, 2^66197506 is an apocalyptic number.

66197506 is a deficient number, since it is larger than the sum of its proper divisors (33098756).

66197506 is a wasteful number, since it uses less digits than its factorization.

66197506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33098755.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 66197506 is about 8136.1849782315. The cubic root of 66197506 is about 404.5267163525.

The spelling of 66197506 in words is "sixty-six million, one hundred ninety-seven thousand, five hundred six".