1661169945 has 16 divisors (see below), whose sum is σ = 2729707200. Its totient is φ = 862012224.

The previous prime is 1661169931. The next prime is 1661169949. The reversal of 1661169945 is 5499611661.

It is not a de Polignac number, because 1661169945 - 2⁴ = 1661169929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1661169894 and 1661169903.

It is not an unprimeable number, because it can be changed into a prime (1661169949) 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 15 ways as a sum of consecutive naturals, for example, 1495995 + ... + 1497104.

It is an arithmetic number, because the mean of its divisors is an integer number (170606700).

Almost surely, 2^1661169945 is an apocalyptic number.

1661169945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661169945 is a deficient number, since it is larger than the sum of its proper divisors (1068537255).

1661169945 is a wasteful number, since it uses less digits than its factorization.

1661169945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2993144.

The product of its digits is 349920, while the sum is 48.

The square root of 1661169945 is about 40757.4526313900. The cubic root of 1661169945 is about 1184.3262491287.

The spelling of 1661169945 in words is "one billion, six hundred sixty-one million, one hundred sixty-nine thousand, nine hundred forty-five".