161235345920 has 240 divisors, whose sum is σ = 426969469080. Its totient is φ = 58349322240.

The previous prime is 161235345889. The next prime is 161235346007. The reversal of 161235345920 is 29543532161.

It can be written as a sum of positive squares in 4 ways, for example, as 161166919936 + 68425984 = 401456^2 + 8272^2 .

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, 70933904 + ... + 70936176.

Almost surely, 2^161235345920 is an apocalyptic number.

161235345920 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 161235345920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213484734540).

161235345920 is an abundant number, since it is smaller than the sum of its proper divisors (265734123160).

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

161235345920 is a wasteful number, since it uses less digits than its factorization.

161235345920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2547 (or 2520 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 41.

The spelling of 161235345920 in words is "one hundred sixty-one billion, two hundred thirty-five million, three hundred forty-five thousand, nine hundred twenty".