189978519809 has 16 divisors (see below), whose sum is σ = 207007460352. Its totient is φ = 173306756928.

The previous prime is 189978519803. The next prime is 189978519811. The reversal of 189978519809 is 908915879981.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189978519809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189978519803) 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, 122672 + ... + 628494.

It is an arithmetic number, because the mean of its divisors is an integer number (12937966272).

Almost surely, 2^189978519809 is an apocalyptic number.

It is an amenable number.

189978519809 is a deficient number, since it is larger than the sum of its proper divisors (17028940543).

189978519809 is a wasteful number, since it uses less digits than its factorization.

189978519809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506176.

The product of its (nonzero) digits is 117573120, while the sum is 74.

The spelling of 189978519809 in words is "one hundred eighty-nine billion, nine hundred seventy-eight million, five hundred nineteen thousand, eight hundred nine".