161668690 has 16 divisors (see below), whose sum is σ = 291159000. Its totient is φ = 64632960.

The previous prime is 161668667. The next prime is 161668721. The reversal of 161668690 is 96866161.

It is a happy number.

161668690 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 124835929 + 36832761 = 11173^2 + 6069^2 .

It is a super-2 number, since 2×161668690² = 52273530652632200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24550 + ... + 30430.

Almost surely, 2^161668690 is an apocalyptic number.

161668690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161668690 is a deficient number, since it is larger than the sum of its proper divisors (129490310).

161668690 is a wasteful number, since it uses less digits than its factorization.

161668690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8637.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 161668690 is about 12714.9003141983. The cubic root of 161668690 is about 544.7643006279.

The spelling of 161668690 in words is "one hundred sixty-one million, six hundred sixty-eight thousand, six hundred ninety".