66723511 has 4 divisors (see below), whose sum is σ = 67010112. Its totient is φ = 66436912.

The previous prime is 66723509. The next prime is 66723539. The reversal of 66723511 is 11532766.

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

It is a cyclic number.

It is not a de Polignac number, because 66723511 - 2¹ = 66723509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66723911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142951 + ... + 143416.

It is an arithmetic number, because the mean of its divisors is an integer number (16752528).

Almost surely, 2^66723511 is an apocalyptic number.

66723511 is a deficient number, since it is larger than the sum of its proper divisors (286601).

66723511 is a wasteful number, since it uses less digits than its factorization.

66723511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286600.

The product of its digits is 7560, while the sum is 31.

The square root of 66723511 is about 8168.4460578497. The cubic root of 66723511 is about 405.5953465375.

The spelling of 66723511 in words is "sixty-six million, seven hundred twenty-three thousand, five hundred eleven".