19971018149 has 2 divisors, whose sum is σ = 19971018150. Its totient is φ = 19971018148.

The previous prime is 19971018131. The next prime is 19971018167. The reversal of 19971018149 is 94181017991.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (19971018131) and next prime (19971018167).

It can be written as a sum of positive squares in only one way, i.e., 15439305025 + 4531713124 = 124255^2 + 67318^2 .

It is a cyclic number.

It is not a de Polignac number, because 19971018149 - 2¹⁶ = 19970952613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19971018097 and 19971018106.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19571018149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9985509074 + 9985509075.

It is an arithmetic number, because the mean of its divisors is an integer number (9985509075).

Almost surely, 2^19971018149 is an apocalyptic number.

It is an amenable number.

19971018149 is a deficient number, since it is larger than the sum of its proper divisors (1).

19971018149 is an equidigital number, since it uses as much as digits as its factorization.

19971018149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 50.

The spelling of 19971018149 in words is "nineteen billion, nine hundred seventy-one million, eighteen thousand, one hundred forty-nine".