33428106721 has 4 divisors (see below), whose sum is σ = 33428546500. Its totient is φ = 33427666944.

The previous prime is 33428106709. The next prime is 33428106727. The reversal of 33428106721 is 12760182433.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 932997025 + 32495109696 = 30545^2 + 180264^2 .

It is a cyclic number.

It is not a de Polignac number, because 33428106721 - 2¹¹ = 33428104673 is a prime.

It is a super-2 number, since 2×33428106721² (a number of 22 digits) contains 22 as substring.

It is a deceptive number, since it divides R_33428106720.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (33428106727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73296 + ... + 268753.

It is an arithmetic number, because the mean of its divisors is an integer number (8357136625).

Almost surely, 2^33428106721 is an apocalyptic number.

33428106721 is the 97729-th nonagonal number.

It is an amenable number.

33428106721 is a deficient number, since it is larger than the sum of its proper divisors (439779).

33428106721 is an equidigital number, since it uses as much as digits as its factorization.

33428106721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439778.

The product of its (nonzero) digits is 48384, while the sum is 37.

The spelling of 33428106721 in words is "thirty-three billion, four hundred twenty-eight million, one hundred six thousand, seven hundred twenty-one".