33661620991 has 4 divisors (see below), whose sum is σ = 34232157000. Its totient is φ = 33091084984.

The previous prime is 33661620989. The next prime is 33661621003. The reversal of 33661620991 is 19902616633.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19902616633 = 115793 ⋅171881.

It is a cyclic number.

It is not a de Polignac number, because 33661620991 - 2¹ = 33661620989 is a prime.

It is a super-2 number, since 2×33661620991² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33661620961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 285267916 + ... + 285268033.

It is an arithmetic number, because the mean of its divisors is an integer number (8558039250).

Almost surely, 2^33661620991 is an apocalyptic number.

33661620991 is a deficient number, since it is larger than the sum of its proper divisors (570536009).

33661620991 is an equidigital number, since it uses as much as digits as its factorization.

33661620991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570536008.

The product of its (nonzero) digits is 314928, while the sum is 46.

The spelling of 33661620991 in words is "thirty-three billion, six hundred sixty-one million, six hundred twenty thousand, nine hundred ninety-one".