1661888383220 has 48 divisors (see below), whose sum is σ = 3774019762128. Its totient is φ = 611074160640.

The previous prime is 1661888383189. The next prime is 1661888383223. The reversal of 1661888383220 is 223838881661.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 285217947364 + 1376670435856 = 534058^2 + 1173316^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661888383223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13198499 + ... + 13323818.

It is an arithmetic number, because the mean of its divisors is an integer number (78625411711).

Almost surely, 2^{1661888383220} is an apocalyptic number.

1661888383220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661888383220 is an abundant number, since it is smaller than the sum of its proper divisors (2112131378908).

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

1661888383220 is a wasteful number, since it uses less digits than its factorization.

1661888383220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26522580 (or 26522578 counting only the distinct ones).

The product of its (nonzero) digits is 5308416, while the sum is 56.

The spelling of 1661888383220 in words is "one trillion, six hundred sixty-one billion, eight hundred eighty-eight million, three hundred eighty-three thousand, two hundred twenty".