33684131981 has 2 divisors, whose sum is σ = 33684131982. Its totient is φ = 33684131980.

The previous prime is 33684131947. The next prime is 33684132043. The reversal of 33684131981 is 18913148633.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32448257956 + 1235874025 = 180134^2 + 35155^2 .

It is a cyclic number.

It is not a de Polignac number, because 33684131981 - 2⁶ = 33684131917 is a prime.

It is a super-2 number, since 2×33684131981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33684139981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16842065990 + 16842065991.

It is an arithmetic number, because the mean of its divisors is an integer number (16842065991).

Almost surely, 2^33684131981 is an apocalyptic number.

It is an amenable number.

33684131981 is a deficient number, since it is larger than the sum of its proper divisors (1).

33684131981 is an equidigital number, since it uses as much as digits as its factorization.

33684131981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 47.

The spelling of 33684131981 in words is "thirty-three billion, six hundred eighty-four million, one hundred thirty-one thousand, nine hundred eighty-one".