1661880945 has 8 divisors (see below), whose sum is σ = 2659009536. Its totient is φ = 886336496.

The previous prime is 1661880901. The next prime is 1661880959. The reversal of 1661880945 is 5490881661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1661880945 - 2⁶ = 1661880881 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1661880894 and 1661880903.

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, 55396017 + ... + 55396046.

It is an arithmetic number, because the mean of its divisors is an integer number (332376192).

Almost surely, 2^1661880945 is an apocalyptic number.

1661880945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661880945 is a deficient number, since it is larger than the sum of its proper divisors (997128591).

1661880945 is a wasteful number, since it uses less digits than its factorization.

1661880945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110792071.

The product of its (nonzero) digits is 414720, while the sum is 48.

The square root of 1661880945 is about 40766.1740294573. The cubic root of 1661880945 is about 1184.4951934838.

The spelling of 1661880945 in words is "one billion, six hundred sixty-one million, eight hundred eighty thousand, nine hundred forty-five".