91814641819 has 4 divisors (see below), whose sum is σ = 91816473544. Its totient is φ = 91812810096.

The previous prime is 91814641817. The next prime is 91814641837.

It is a happy number.

91814641819 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 91814641819 - 2¹ = 91814641817 is a prime.

It is a super-2 number, since 2×91814641819² (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 (91814641813) 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, 838497 + ... + 941650.

It is an arithmetic number, because the mean of its divisors is an integer number (22954118386).

Almost surely, 2^91814641819 is an apocalyptic number.

91814641819 is a deficient number, since it is larger than the sum of its proper divisors (1831725).

91814641819 is a wasteful number, since it uses less digits than its factorization.

91814641819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1831724.

The product of its digits is 497664, while the sum is 52.

The spelling of 91814641819 in words is "ninety-one billion, eight hundred fourteen million, six hundred forty-one thousand, eight hundred nineteen".