161961602220 has 384 divisors, whose sum is σ = 560733788160. Its totient is φ = 38482560000.

The previous prime is 161961602197. The next prime is 161961602251. The reversal of 161961602220 is 22206169161.

161961602220 is a `hidden beast` number, since 1 + 6 + 19 + 616 + 0 + 2 + 2 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 61792510 + ... + 61795130.

It is an arithmetic number, because the mean of its divisors is an integer number (1460244240).

Almost surely, 2^161961602220 is an apocalyptic number.

161961602220 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 161961602220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280366894080).

161961602220 is an abundant number, since it is smaller than the sum of its proper divisors (398772185940).

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

161961602220 is a wasteful number, since it uses less digits than its factorization.

161961602220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2854 (or 2846 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The spelling of 161961602220 in words is "one hundred sixty-one billion, nine hundred sixty-one million, six hundred two thousand, two hundred twenty".