161211700 has 72 divisors (see below), whose sum is σ = 378960120. Its totient is φ = 59174400.

The previous prime is 161211683. The next prime is 161211703. The reversal of 161211700 is 7112161.

It can be written as a sum of positive squares in 12 ways, for example, as 126023076 + 35188624 = 11226^2 + 5932^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161211703) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 349470 + ... + 349930.

It is an arithmetic number, because the mean of its divisors is an integer number (5263335).

Almost surely, 2^161211700 is an apocalyptic number.

161211700 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 161211700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189480060).

161211700 is an abundant number, since it is smaller than the sum of its proper divisors (217748420).

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

161211700 is a wasteful number, since it uses less digits than its factorization.

161211700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 19.

The square root of 161211700 is about 12696.9169486139. The cubic root of 161211700 is about 544.2505198867.

Adding to 161211700 its reverse (7112161), we get a palindrome (168323861).

The spelling of 161211700 in words is "one hundred sixty-one million, two hundred eleven thousand, seven hundred".