191900001001 has 8 divisors (see below), whose sum is σ = 205971638184. Its totient is φ = 178137630720.

The previous prime is 191900000953. The next prime is 191900001011. The reversal of 191900001001 is 100100009191.

It can be written as a sum of positive squares in 4 ways, for example, as 55025899776 + 136874101225 = 234576^2 + 369965^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 191900001001 - 2⁹ = 191900000489 is a prime.

It is a super-2 number, since 2×191900001001² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191900001011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77315440 + ... + 77317921.

It is an arithmetic number, because the mean of its divisors is an integer number (25746454773).

Almost surely, 2^191900001001 is an apocalyptic number.

It is an amenable number.

191900001001 is a deficient number, since it is larger than the sum of its proper divisors (14071637183).

191900001001 is a wasteful number, since it uses less digits than its factorization.

191900001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154633451.

The product of its (nonzero) digits is 81, while the sum is 22.

The spelling of 191900001001 in words is "one hundred ninety-one billion, nine hundred million, one thousand, one".