1661164642500 has 240 divisors, whose sum is σ = 5286191877120. Its totient is φ = 402526800000.

The previous prime is 1661164642427. The next prime is 1661164642517. The reversal of 1661164642500 is 52464611661.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 349055121 + ... + 349059879.

It is an arithmetic number, because the mean of its divisors is an integer number (22025799488).

Almost surely, 2^{1661164642500} is an apocalyptic number.

1661164642500 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 1661164642500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2643095938560).

1661164642500 is an abundant number, since it is smaller than the sum of its proper divisors (3625027234620).

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

1661164642500 is a wasteful number, since it uses less digits than its factorization.

1661164642500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9028 (or 9011 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 1661164642500 in words is "one trillion, six hundred sixty-one billion, one hundred sixty-four million, six hundred forty-two thousand, five hundred".