66120731 has 4 divisors (see below), whose sum is σ = 66359712. Its totient is φ = 65881752.

The previous prime is 66120727. The next prime is 66120749. The reversal of 66120731 is 13702166.

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 66120731 - 2² = 66120727 is a prime.

It is a super-2 number, since 2×66120731² = 8743902135948722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66120731.

It is not an unprimeable number, because it can be changed into a prime (66120781) 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, 119075 + ... + 119628.

It is an arithmetic number, because the mean of its divisors is an integer number (16589928).

Almost surely, 2^66120731 is an apocalyptic number.

66120731 is a deficient number, since it is larger than the sum of its proper divisors (238981).

66120731 is a wasteful number, since it uses less digits than its factorization.

66120731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238980.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 66120731 is about 8131.4654890739. The cubic root of 66120731 is about 404.3702675929.

Adding to 66120731 its reverse (13702166), we get a palindrome (79822897).

The spelling of 66120731 in words is "sixty-six million, one hundred twenty thousand, seven hundred thirty-one".