66720106 has 4 divisors (see below), whose sum is σ = 100080162. Its totient is φ = 33360052.

The previous prime is 66720103. The next prime is 66720107. The reversal of 66720106 is 60102766.

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., 64144081 + 2576025 = 8009^2 + 1605^2 .

It is not an unprimeable number, because it can be changed into a prime (66720103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16680025 + ... + 16680028.

Almost surely, 2^66720106 is an apocalyptic number.

66720106 is a deficient number, since it is larger than the sum of its proper divisors (33360056).

66720106 is a wasteful number, since it uses less digits than its factorization.

66720106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33360055.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 66720106 is about 8168.2376312152. The cubic root of 66720106 is about 405.5884470422.

The spelling of 66720106 in words is "sixty-six million, seven hundred twenty thousand, one hundred six".