2157561986220 has 144 divisors (see below), whose sum is σ = 6771241451520. Its totient is φ = 555431385600.

The previous prime is 2157561986207. The next prime is 2157561986273. The reversal of 2157561986220 is 226891657512.

2157561986220 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 5 + 6 + 1 + 9 + 8 + 622 + 0 = 666.

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, 42731790 + ... + 42782250.

It is an arithmetic number, because the mean of its divisors is an integer number (47022510080).

Almost surely, 2^{2157561986220} is an apocalyptic number.

2157561986220 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 2157561986220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3385620725760).

2157561986220 is an abundant number, since it is smaller than the sum of its proper divisors (4613679465300).

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

2157561986220 is a wasteful number, since it uses less digits than its factorization.

2157561986220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58696 (or 58691 counting only the distinct ones).

The product of its (nonzero) digits is 3628800, while the sum is 54.

The spelling of 2157561986220 in words is "two trillion, one hundred fifty-seven billion, five hundred sixty-one million, nine hundred eighty-six thousand, two hundred twenty".