1661688675 has 54 divisors (see below), whose sum is σ = 3092414052. Its totient is φ = 884539440.

The previous prime is 1661688671. The next prime is 1661688697. The reversal of 1661688675 is 5768861661.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

1661688675 is a `hidden beast` number, since 16 + 616 + 8 + 8 + 6 + 7 + 5 = 666.

1661688675 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1661688675 - 2² = 1661688671 is a prime.

It is a super-2 number, since 2×1661688675² = 5522418505246511250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661688671) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 3176964 + ... + 3177486.

Almost surely, 2^1661688675 is an apocalyptic number.

1661688675 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661688675 is a deficient number, since it is larger than the sum of its proper divisors (1430725377).

1661688675 is an frugal number, since it uses more digits than its factorization.

1661688675 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1071 (or 531 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The square root of 1661688675 is about 40763.8157561335. The cubic root of 1661688675 is about 1184.4495119776.

The spelling of 1661688675 in words is "one billion, six hundred sixty-one million, six hundred eighty-eight thousand, six hundred seventy-five".