2161656911940 has 96 divisors (see below), whose sum is σ = 6130846181376. Its totient is φ = 569005557120.

The previous prime is 2161656911893. The next prime is 2161656911957. The reversal of 2161656911940 is 491196561612.

It is a happy number.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5605125 + ... + 5978355.

It is an arithmetic number, because the mean of its divisors is an integer number (63862981056).

Almost surely, 2^{2161656911940} is an apocalyptic number.

2161656911940 is a gapful number since it is divisible by the number (20) 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 2161656911940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3065423090688).

2161656911940 is an abundant number, since it is smaller than the sum of its proper divisors (3969189269436).

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

2161656911940 is a wasteful number, since it uses less digits than its factorization.

2161656911940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374489 (or 374487 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 51.

The spelling of 2161656911940 in words is "two trillion, one hundred sixty-one billion, six hundred fifty-six million, nine hundred eleven thousand, nine hundred forty".