66561412131 has 24 divisors (see below), whose sum is σ = 98948946096. Its totient is φ = 43091737920.

The previous prime is 66561412117. The next prime is 66561412133. The reversal of 66561412131 is 13121416566.

66561412131 is a `hidden beast` number, since 6 + 6 + 5 + 614 + 1 + 2 + 1 + 31 = 666.

It is not a de Polignac number, because 66561412131 - 2¹³ = 66561403939 is a prime.

It is a super-2 number, since 2×66561412131² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66561412133) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 430140 + ... + 564041.

It is an arithmetic number, because the mean of its divisors is an integer number (4122872754).

Almost surely, 2^66561412131 is an apocalyptic number.

66561412131 is a deficient number, since it is larger than the sum of its proper divisors (32387533965).

66561412131 is a wasteful number, since it uses less digits than its factorization.

66561412131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994403 (or 994400 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

Adding to 66561412131 its reverse (13121416566), we get a palindrome (79682828697).

The spelling of 66561412131 in words is "sixty-six billion, five hundred sixty-one million, four hundred twelve thousand, one hundred thirty-one".