133616781 has 12 divisors (see below), whose sum is σ = 197491008. Its totient is φ = 87006024.

The previous prime is 133616761. The next prime is 133616801. The reversal of 133616781 is 187616331.

133616781 is a `hidden beast` number, since 1 + 33 + 616 + 7 + 8 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (133616761) and next prime (133616801).

It is not a de Polignac number, because 133616781 - 2⁷ = 133616653 is a prime.

It is a super-2 number, since 2×133616781² = 35706888329603922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133616711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 172245 + ... + 173018.

It is an arithmetic number, because the mean of its divisors is an integer number (16457584).

Almost surely, 2^133616781 is an apocalyptic number.

It is an amenable number.

133616781 is a deficient number, since it is larger than the sum of its proper divisors (63874227).

133616781 is a wasteful number, since it uses less digits than its factorization.

133616781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345312 (or 345309 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 133616781 is about 11559.2725117111. The cubic root of 133616781 is about 511.2347130689.

The spelling of 133616781 in words is "one hundred thirty-three million, six hundred sixteen thousand, seven hundred eighty-one".