1661167755 has 72 divisors (see below), whose sum is σ = 3253786848. Its totient is φ = 782166528.

The previous prime is 1661167751. The next prime is 1661167811. The reversal of 1661167755 is 5577611661.

It is not a de Polignac number, because 1661167755 - 2² = 1661167751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1661167755.

It is not an unprimeable number, because it can be changed into a prime (1661167751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 170167 + ... + 179663.

It is an arithmetic number, because the mean of its divisors is an integer number (45191484).

Almost surely, 2^1661167755 is an apocalyptic number.

1661167755 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661167755 is a deficient number, since it is larger than the sum of its proper divisors (1592619093).

1661167755 is a wasteful number, since it uses less digits than its factorization.

1661167755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9557 (or 9541 counting only the distinct ones).

The product of its digits is 264600, while the sum is 45.

The square root of 1661167755 is about 40757.4257651290. The cubic root of 1661167755 is about 1184.3257286771.

The spelling of 1661167755 in words is "one billion, six hundred sixty-one million, one hundred sixty-seven thousand, seven hundred fifty-five".