1661164785 has 48 divisors (see below), whose sum is σ = 3310978944. Its totient is φ = 754707456.

The previous prime is 1661164783. The next prime is 1661164789. The reversal of 1661164785 is 5874611661.

1661164785 is a `hidden beast` number, since 1 + 66 + 116 + 478 + 5 = 666.

It is not a de Polignac number, because 1661164785 - 2¹ = 1661164783 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1661164785.

It is not an unprimeable number, because it can be changed into a prime (1661164783) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 35169 + ... + 67521.

It is an arithmetic number, because the mean of its divisors is an integer number (68978728).

Almost surely, 2^1661164785 is an apocalyptic number.

1661164785 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661164785 is a deficient number, since it is larger than the sum of its proper divisors (1649814159).

1661164785 is a wasteful number, since it uses less digits than its factorization.

1661164785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32534 (or 32531 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 1661164785 is about 40757.3893300344. The cubic root of 1661164785 is about 1184.3250228585.

The spelling of 1661164785 in words is "one billion, six hundred sixty-one million, one hundred sixty-four thousand, seven hundred eighty-five".