66781131 has 4 divisors (see below), whose sum is σ = 89041512. Its totient is φ = 44520752.

The previous prime is 66781123. The next prime is 66781147. The reversal of 66781131 is 13118766.

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 66781131 - 2³ = 66781123 is a prime.

It is a super-2 number, since 2×66781131² = 8919438915278322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66781092 and 66781101.

It is not an unprimeable number, because it can be changed into a prime (66781331) 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, 11130186 + ... + 11130191.

It is an arithmetic number, because the mean of its divisors is an integer number (22260378).

Almost surely, 2^66781131 is an apocalyptic number.

66781131 is a deficient number, since it is larger than the sum of its proper divisors (22260381).

66781131 is a wasteful number, since it uses less digits than its factorization.

66781131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22260380.

The product of its digits is 6048, while the sum is 33.

The square root of 66781131 is about 8171.9722833598. The cubic root of 66781131 is about 405.7120654144.

Adding to 66781131 its reverse (13118766), we get a palindrome (79899897).

The spelling of 66781131 in words is "sixty-six million, seven hundred eighty-one thousand, one hundred thirty-one".