1661057837500 has 72 divisors (see below), whose sum is σ = 3641773286592. Its totient is φ = 662879400000.

The previous prime is 1661057837489. The next prime is 1661057837501. The reversal of 1661057837500 is 57387501661.

It is a super-2 number, since 2×1661057837500² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661057837501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5233342 + ... + 5541658.

It is an arithmetic number, because the mean of its divisors is an integer number (50580184536).

Almost surely, 2^{1661057837500} is an apocalyptic number.

1661057837500 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 1661057837500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1820886643296).

1661057837500 is an abundant number, since it is smaller than the sum of its proper divisors (1980715449092).

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

1661057837500 is an equidigital number, since it uses as much as digits as its factorization.

1661057837500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308777 (or 308755 counting only the distinct ones).

The product of its (nonzero) digits is 1058400, while the sum is 49.

The spelling of 1661057837500 in words is "one trillion, six hundred sixty-one billion, fifty-seven million, eight hundred thirty-seven thousand, five hundred".