161666719 has 8 divisors (see below), whose sum is σ = 171447408. Its totient is φ = 151916160.

The previous prime is 161666717. The next prime is 161666777. The reversal of 161666719 is 917666161.

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 161666719 - 2¹ = 161666717 is a prime.

It is a super-2 number, since 2×161666719² = 52272256064449922, 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 (161666711) 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, 4044 + ... + 18430.

It is an arithmetic number, because the mean of its divisors is an integer number (21430926).

Almost surely, 2^161666719 is an apocalyptic number.

161666719 is a deficient number, since it is larger than the sum of its proper divisors (9780689).

161666719 is a wasteful number, since it uses less digits than its factorization.

161666719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15065.

The product of its digits is 81648, while the sum is 43.

The square root of 161666719 is about 12714.8228064728. The cubic root of 161666719 is about 544.7620867694.

The spelling of 161666719 in words is "one hundred sixty-one million, six hundred sixty-six thousand, seven hundred nineteen".