18901591249 has 2 divisors, whose sum is σ = 18901591250. Its totient is φ = 18901591248.

The previous prime is 18901591243. The next prime is 18901591259. The reversal of 18901591249 is 94219510981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12414416400 + 6487174849 = 111420^2 + 80543^2 .

It is an emirp because it is prime and its reverse (94219510981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18901591249 is a prime.

It is not a weakly prime, because it can be changed into another prime (18901591243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9450795624 + 9450795625.

It is an arithmetic number, because the mean of its divisors is an integer number (9450795625).

Almost surely, 2^18901591249 is an apocalyptic number.

It is an amenable number.

18901591249 is a deficient number, since it is larger than the sum of its proper divisors (1).

18901591249 is an equidigital number, since it uses as much as digits as its factorization.

18901591249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 49.

The spelling of 18901591249 in words is "eighteen billion, nine hundred one million, five hundred ninety-one thousand, two hundred forty-nine".