1661977473 has 8 divisors (see below), whose sum is σ = 2386429248. Its totient is φ = 1022755344.

The previous prime is 1661977451. The next prime is 1661977489. The reversal of 1661977473 is 3747791661.

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

It is not a de Polignac number, because 1661977473 - 2⁵ = 1661977441 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1661977403) 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, 21307365 + ... + 21307442.

It is an arithmetic number, because the mean of its divisors is an integer number (298303656).

Almost surely, 2^1661977473 is an apocalyptic number.

1661977473 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1661977473 is a deficient number, since it is larger than the sum of its proper divisors (724451775).

1661977473 is a wasteful number, since it uses less digits than its factorization.

1661977473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42614823.

The product of its digits is 1333584, while the sum is 51.

The square root of 1661977473 is about 40767.3579349950. The cubic root of 1661977473 is about 1184.5181262815.

The spelling of 1661977473 in words is "one billion, six hundred sixty-one million, nine hundred seventy-seven thousand, four hundred seventy-three".