161218973 has 8 divisors (see below), whose sum is σ = 171315000. Its totient is φ = 151191040.

The previous prime is 161218969. The next prime is 161218987. The reversal of 161218973 is 379812161.

It can be written as a sum of positive squares in 4 ways, for example, as 96786244 + 64432729 = 9838^2 + 8027^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161218973 - 2² = 161218969 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161218943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12098 + ... + 21651.

It is an arithmetic number, because the mean of its divisors is an integer number (21414375).

Almost surely, 2^161218973 is an apocalyptic number.

It is an amenable number.

161218973 is a deficient number, since it is larger than the sum of its proper divisors (10096027).

161218973 is a wasteful number, since it uses less digits than its factorization.

161218973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34047.

The product of its digits is 18144, while the sum is 38.

The square root of 161218973 is about 12697.2033534948. The cubic root of 161218973 is about 544.2587043103.

The spelling of 161218973 in words is "one hundred sixty-one million, two hundred eighteen thousand, nine hundred seventy-three".