161661733 has 4 divisors (see below), whose sum is σ = 168690528. Its totient is φ = 154632940.

The previous prime is 161661707. The next prime is 161661739. The reversal of 161661733 is 337166161.

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, and also an emirpimes, since its reverse is a distinct semiprime: 337166161 = 593 ⋅568577.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161661733 is a prime.

It is a super-2 number, since 2×161661733² = 52269031833126578, 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 (161661739) 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, 3514363 + ... + 3514408.

It is an arithmetic number, because the mean of its divisors is an integer number (42172632).

Almost surely, 2^161661733 is an apocalyptic number.

It is an amenable number.

161661733 is a deficient number, since it is larger than the sum of its proper divisors (7028795).

161661733 is an equidigital number, since it uses as much as digits as its factorization.

161661733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7028794.

The product of its digits is 13608, while the sum is 34.

The square root of 161661733 is about 12714.6267345919. The cubic root of 161661733 is about 544.7564863347.

The spelling of 161661733 in words is "one hundred sixty-one million, six hundred sixty-one thousand, seven hundred thirty-three".