161869491 has 36 divisors (see below), whose sum is σ = 273156312. Its totient is φ = 92098944.

The previous prime is 161869489. The next prime is 161869541. The reversal of 161869491 is 194968161.

It is not a de Polignac number, because 161869491 - 2¹ = 161869489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161869441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 124155 + ... + 125451.

Almost surely, 2^161869491 is an apocalyptic number.

161869491 is a deficient number, since it is larger than the sum of its proper divisors (111286821).

161869491 is a wasteful number, since it uses less digits than its factorization.

161869491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1600 (or 1590 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 161869491 is about 12722.7941506573. The cubic root of 161869491 is about 544.9897492671.

The spelling of 161869491 in words is "one hundred sixty-one million, eight hundred sixty-nine thousand, four hundred ninety-one".