91000000019 has 4 divisors (see below), whose sum is σ = 92491803360. Its totient is φ = 89508196680.

The previous prime is 90999999973. The next prime is 91000000037.

91000000019 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91000000019 - 2⁸ = 90999999763 is a prime.

It is a super-2 number, since 2×91000000019² (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 (91000000099) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 745901579 + ... + 745901700.

It is an arithmetic number, because the mean of its divisors is an integer number (23122950840).

Almost surely, 2^91000000019 is an apocalyptic number.

91000000019 is a deficient number, since it is larger than the sum of its proper divisors (1491803341).

91000000019 is a wasteful number, since it uses less digits than its factorization.

91000000019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1491803340.

The product of its (nonzero) digits is 81, while the sum is 20.

It can be divided in two parts, 910000000 and 19, that added together give a palindrome (910000019).

The spelling of 91000000019 in words is "ninety-one billion, nineteen", and thus it is an aban number and an uban number.