1669607640981 has 12 divisors (see below), whose sum is σ = 2756177693152. Its totient is φ = 954061509096.

The previous prime is 1669607640947. The next prime is 1669607640983. The reversal of 1669607640981 is 1890467069661.

1669607640981 is a `hidden beast` number, since 1 + 66 + 96 + 0 + 7 + 6 + 409 + 81 = 666.

It is not a de Polignac number, because 1669607640981 - 2¹³ = 1669607632789 is a prime.

It is a super-2 number, since 2×1669607640981² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63), and also a Moran number because the ratio is a prime number: 26501708587 = 1669607640981 / (1 + 6 + 6 + 9 + 6 + 0 + 7 + 6 + 4 + 0 + 9 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1669607640983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13250854231 + ... + 13250854356.

Almost surely, 2^{1669607640981} is an apocalyptic number.

It is an amenable number.

1669607640981 is a deficient number, since it is larger than the sum of its proper divisors (1086570052171).

1669607640981 is a wasteful number, since it uses less digits than its factorization.

1669607640981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26501708600 (or 26501708597 counting only the distinct ones).

The product of its (nonzero) digits is 23514624, while the sum is 63.

The spelling of 1669607640981 in words is "one trillion, six hundred sixty-nine billion, six hundred seven million, six hundred forty thousand, nine hundred eighty-one".