1661506611136 has 168 divisors, whose sum is σ = 3622511033856. Its totient is φ = 755172618240.

The previous prime is 1661506611109. The next prime is 1661506611137. The reversal of 1661506611136 is 6311166051661.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1661506611092 and 1661506611101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661506611137) 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, 322808115 + ... + 322813261.

Almost surely, 2^{1661506611136} is an apocalyptic number.

1661506611136 is a gapful number since it is divisible by the number (16) 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 1661506611136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1811255516928).

1661506611136 is an abundant number, since it is smaller than the sum of its proper divisors (1961004422720).

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

1661506611136 is a wasteful number, since it uses less digits than its factorization.

1661506611136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5787 (or 5760 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The spelling of 1661506611136 in words is "one trillion, six hundred sixty-one billion, five hundred six million, six hundred eleven thousand, one hundred thirty-six".