1661155788 has 24 divisors (see below), whose sum is σ = 4080032320. Its totient is φ = 524575440.

The previous prime is 1661155781. The next prime is 1661155789. The reversal of 1661155788 is 8875511661.

It is a happy number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (1661155781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3642658 + ... + 3643113.

Almost surely, 2^1661155788 is an apocalyptic number.

It is an amenable number.

1661155788 is an abundant number, since it is smaller than the sum of its proper divisors (2418876532).

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

1661155788 is a wasteful number, since it uses less digits than its factorization.

1661155788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7285797 (or 7285795 counting only the distinct ones).

The product of its digits is 403200, while the sum is 48.

The square root of 1661155788 is about 40757.2789572611. The cubic root of 1661155788 is about 1184.3228847219.

The spelling of 1661155788 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, seven hundred eighty-eight".