1661155552 has 72 divisors (see below), whose sum is σ = 3842055504. Its totient is φ = 692554752.

The previous prime is 1661155543. The next prime is 1661155591. The reversal of 1661155552 is 2555511661.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 303948 + ... + 309364.

It is an arithmetic number, because the mean of its divisors is an integer number (53361882).

Almost surely, 2^1661155552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661155552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1921027752).

1661155552 is an abundant number, since it is smaller than the sum of its proper divisors (2180899952).

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

1661155552 is an equidigital number, since it uses as much as digits as its factorization.

1661155552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5508 (or 5463 counting only the distinct ones).

The product of its digits is 45000, while the sum is 37.

The square root of 1661155552 is about 40757.2760620726. The cubic root of 1661155552 is about 1184.3228286364.

The spelling of 1661155552 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, five hundred fifty-two".