161972919 has 16 divisors (see below), whose sum is σ = 245814240. Its totient is φ = 105347520.

The previous prime is 161972903. The next prime is 161972933. The reversal of 161972919 is 919279161.

161972919 is a `hidden beast` number, since 1 + 619 + 7 + 29 + 1 + 9 = 666.

It is not a de Polignac number, because 161972919 - 2⁴ = 161972903 is a prime.

It is a super-3 number, since 3×161972919³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161972999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72052 + ... + 74265.

It is an arithmetic number, because the mean of its divisors is an integer number (15363390).

Almost surely, 2^161972919 is an apocalyptic number.

161972919 is a deficient number, since it is larger than the sum of its proper divisors (83841321).

161972919 is a wasteful number, since it uses less digits than its factorization.

161972919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146367 (or 146361 counting only the distinct ones).

The product of its digits is 61236, while the sum is 45.

The square root of 161972919 is about 12726.8581747421. The cubic root of 161972919 is about 545.1057999576.

The spelling of 161972919 in words is "one hundred sixty-one million, nine hundred seventy-two thousand, nine hundred nineteen".