1661831788 has 24 divisors (see below), whose sum is σ = 3061523808. Its totient is φ = 787750656.

The previous prime is 1661831761. The next prime is 1661831791. The reversal of 1661831788 is 8871381661.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69531 + ... + 90322.

It is an arithmetic number, because the mean of its divisors is an integer number (127563492).

Almost surely, 2^1661831788 is an apocalyptic number.

It is an amenable number.

1661831788 is a deficient number, since it is larger than the sum of its proper divisors (1399692020).

1661831788 is a wasteful number, since it uses less digits than its factorization.

1661831788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159993 (or 159991 counting only the distinct ones).

The product of its digits is 387072, while the sum is 49.

The square root of 1661831788 is about 40765.5711109264. The cubic root of 1661831788 is about 1184.4835145878.

The spelling of 1661831788 in words is "one billion, six hundred sixty-one million, eight hundred thirty-one thousand, seven hundred eighty-eight".