161884690 has 48 divisors (see below), whose sum is σ = 322050456. Its totient is φ = 58544640.

The previous prime is 161884661. The next prime is 161884703. The reversal of 161884690 is 96488161.

It can be written as a sum of positive squares in 4 ways, for example, as 125148969 + 36735721 = 11187^2 + 6061^2 .

It is a super-2 number, since 2×161884690² = 52413305712792200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 407572 + ... + 407968.

Almost surely, 2^161884690 is an apocalyptic number.

161884690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161884690 is a deficient number, since it is larger than the sum of its proper divisors (160165766).

161884690 is a wasteful number, since it uses less digits than its factorization.

161884690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763 (or 752 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 161884690 is about 12723.3914503956. The cubic root of 161884690 is about 545.0068063005.

The spelling of 161884690 in words is "one hundred sixty-one million, eight hundred eighty-four thousand, six hundred ninety".