161221122000 has 480 divisors, whose sum is σ = 591232801536. Its totient is φ = 40867200000.

The previous prime is 161221121983. The next prime is 161221122053. The reversal of 161221122000 is 221122161.

161221122000 is a `hidden beast` number, since 1 + 612 + 21 + 12 + 20 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 71620875 + ... + 71623125.

Almost surely, 2^161221122000 is an apocalyptic number.

161221122000 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 161221122000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (295616400768).

161221122000 is an abundant number, since it is smaller than the sum of its proper divisors (430011679536).

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

161221122000 is a wasteful number, since it uses less digits than its factorization.

161221122000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2476 (or 2457 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 161221122000 its reverse (221122161), we get a palindrome (161442244161).

The spelling of 161221122000 in words is "one hundred sixty-one billion, two hundred twenty-one million, one hundred twenty-two thousand".