1661560667 has 8 divisors (see below), whose sum is σ = 1789690224. Its totient is φ = 1533476448.

The previous prime is 1661560657. The next prime is 1661560679. The reversal of 1661560667 is 7660651661.

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 1661560667 - 2¹⁸ = 1661298523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661560657) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131948 + ... + 143990.

It is an arithmetic number, because the mean of its divisors is an integer number (223711278).

Almost surely, 2^1661560667 is an apocalyptic number.

1661560667 is a deficient number, since it is larger than the sum of its proper divisors (128129557).

1661560667 is a wasteful number, since it uses less digits than its factorization.

1661560667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22669.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 1661560667 is about 40762.2456079152. The cubic root of 1661560667 is about 1184.4190965516.

The spelling of 1661560667 in words is "one billion, six hundred sixty-one million, five hundred sixty thousand, six hundred sixty-seven".