161706121700 has 72 divisors (see below), whose sum is σ = 357832050408. Its totient is φ = 63407185920.

The previous prime is 161706121693. The next prime is 161706121711. The reversal of 161706121700 is 7121607161.

It can be written as a sum of positive squares in 12 ways, for example, as 64906733824 + 96799387876 = 254768^2 + 311126^2 .

It is a super-2 number, since 2×161706121700² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6416324 + ... + 6441476.

It is an arithmetic number, because the mean of its divisors is an integer number (4969889589).

Almost surely, 2^161706121700 is an apocalyptic number.

161706121700 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161706121700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178916025204).

161706121700 is an abundant number, since it is smaller than the sum of its proper divisors (196125928708).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161706121700 is a wasteful number, since it uses less digits than its factorization.

161706121700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26433 (or 26426 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 32.

Adding to 161706121700 its reverse (7121607161), we get a palindrome (168827728861).

The spelling of 161706121700 in words is "one hundred sixty-one billion, seven hundred six million, one hundred twenty-one thousand, seven hundred".