189945978669 has 16 divisors (see below), whose sum is σ = 285601474240. Its totient is φ = 124740641520.

The previous prime is 189945978667. The next prime is 189945978679. The reversal of 189945978669 is 966879549981.

189945978669 is a `hidden beast` number, since 1 + 8 + 99 + 459 + 78 + 6 + 6 + 9 = 666.

It is not a de Polignac number, because 189945978669 - 2¹ = 189945978667 is a prime.

It is a super-2 number, since 2×189945978669² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189945978667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52498462 + ... + 52502079.

It is an arithmetic number, because the mean of its divisors is an integer number (17850092140).

Almost surely, 2^189945978669 is an apocalyptic number.

It is an amenable number.

189945978669 is a deficient number, since it is larger than the sum of its proper divisors (95655495571).

189945978669 is a wasteful number, since it uses less digits than its factorization.

189945978669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105000617 (or 105000611 counting only the distinct ones).

The product of its digits is 2116316160, while the sum is 81.

The spelling of 189945978669 in words is "one hundred eighty-nine billion, nine hundred forty-five million, nine hundred seventy-eight thousand, six hundred sixty-nine".