161989733 has 4 divisors (see below), whose sum is σ = 162042528. Its totient is φ = 161936940.

The previous prime is 161989721. The next prime is 161989741. The reversal of 161989733 is 337989161.

It is a happy number.

161989733 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161989733 is a prime.

It is a super-2 number, since 2×161989733² = 52481347194822578, which 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 (161989703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21491 + ... + 28032.

It is an arithmetic number, because the mean of its divisors is an integer number (40510632).

Almost surely, 2^161989733 is an apocalyptic number.

It is an amenable number.

161989733 is a deficient number, since it is larger than the sum of its proper divisors (52795).

161989733 is an equidigital number, since it uses as much as digits as its factorization.

161989733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52794.

The product of its digits is 244944, while the sum is 47.

The square root of 161989733 is about 12727.5187291161. The cubic root of 161989733 is about 545.1246613242.

The spelling of 161989733 in words is "one hundred sixty-one million, nine hundred eighty-nine thousand, seven hundred thirty-three".