18949399397 has 2 divisors, whose sum is σ = 18949399398. Its totient is φ = 18949399396.

The previous prime is 18949399369. The next prime is 18949399423. The reversal of 18949399397 is 79399394981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16079761636 + 2869637761 = 126806^2 + 53569^2 .

It is a cyclic number.

It is not a de Polignac number, because 18949399397 - 2⁸ = 18949399141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18949399397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18949399097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9474699698 + 9474699699.

It is an arithmetic number, because the mean of its divisors is an integer number (9474699699).

Almost surely, 2^18949399397 is an apocalyptic number.

It is an amenable number.

18949399397 is a deficient number, since it is larger than the sum of its proper divisors (1).

18949399397 is an equidigital number, since it uses as much as digits as its factorization.

18949399397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 119042784, while the sum is 71.

The spelling of 18949399397 in words is "eighteen billion, nine hundred forty-nine million, three hundred ninety-nine thousand, three hundred ninety-seven".