1661128955 has 16 divisors (see below), whose sum is σ = 2059665408. Its totient is φ = 1284780000.

The previous prime is 1661128951. The next prime is 1661128957. The reversal of 1661128955 is 5598211661.

It is not a de Polignac number, because 1661128955 - 2² = 1661128951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661128951) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173750 + ... + 183060.

It is an arithmetic number, because the mean of its divisors is an integer number (128729088).

Almost surely, 2^1661128955 is an apocalyptic number.

1661128955 is a deficient number, since it is larger than the sum of its proper divisors (398536453).

1661128955 is a wasteful number, since it uses less digits than its factorization.

1661128955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10498.

The product of its digits is 129600, while the sum is 44.

The square root of 1661128955 is about 40756.9497754677. The cubic root of 1661128955 is about 1184.3165078151.

The spelling of 1661128955 in words is "one billion, six hundred sixty-one million, one hundred twenty-eight thousand, nine hundred fifty-five".