2161997509056 has 336 divisors, whose sum is σ = 7279482804480. Its totient is φ = 559983943680.

The previous prime is 2161997509019. The next prime is 2161997509073. The reversal of 2161997509056 is 6509057991612.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×2161997509056² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 37123096 + ... + 37181288.

Almost surely, 2^{2161997509056} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2161997509056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3639741402240).

2161997509056 is an abundant number, since it is smaller than the sum of its proper divisors (5117485295424).

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

2161997509056 is a wasteful number, since it uses less digits than its factorization.

2161997509056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58592 (or 58575 counting only the distinct ones).

The product of its (nonzero) digits is 9185400, while the sum is 60.

The spelling of 2161997509056 in words is "two trillion, one hundred sixty-one billion, nine hundred ninety-seven million, five hundred nine thousand, fifty-six".