161229968640 has 1440 divisors, whose sum is σ = 660776520096. Its totient is φ = 37265080320.

The previous prime is 161229968629. The next prime is 161229968671. The reversal of 161229968640 is 46869922161.

It can be written as a sum of positive squares in 16 ways, for example, as 54285272064 + 106944696576 = 232992^2 + 327024^2 .

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 2643114210 + ... + 2643114270.

Almost surely, 2^161229968640 is an apocalyptic number.

161229968640 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 161229968640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330388260048).

161229968640 is an abundant number, since it is smaller than the sum of its proper divisors (499546551456).

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

161229968640 is a wasteful number, since it uses less digits than its factorization.

161229968640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The spelling of 161229968640 in words is "one hundred sixty-one billion, two hundred twenty-nine million, nine hundred sixty-eight thousand, six hundred forty".