161689970 has 32 divisors (see below), whose sum is σ = 314299440. Its totient is φ = 59535360.

The previous prime is 161689951. The next prime is 161689973. The reversal of 161689970 is 79986161.

It can be written as a sum of positive squares in 8 ways, for example, as 126180289 + 35509681 = 11233^2 + 5959^2 .

It is a super-2 number, since 2×161689970² = 52287292797201800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161689973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51650 + ... + 54690.

Almost surely, 2^161689970 is an apocalyptic number.

161689970 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161689970 is a deficient number, since it is larger than the sum of its proper divisors (152609470).

161689970 is a wasteful number, since it uses less digits than its factorization.

161689970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3470.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 161689970 is about 12715.7371001448. The cubic root of 161689970 is about 544.7882015158.

The spelling of 161689970 in words is "one hundred sixty-one million, six hundred eighty-nine thousand, nine hundred seventy".