19867526643397 has 2 divisors, whose sum is σ = 19867526643398. Its totient is φ = 19867526643396.

The previous prime is 19867526643383. The next prime is 19867526643401. The reversal of 19867526643397 is 79334662576891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19412712632196 + 454814011201 = 4405986^2 + 674399^2 .

It is a cyclic number.

It is not a de Polignac number, because 19867526643397 - 2³⁹ = 19317770829509 is a prime.

It is a super-2 number, since 2×19867526643397² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19867526643337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9933763321698 + 9933763321699.

It is an arithmetic number, because the mean of its divisors is an integer number (9933763321699).

Almost surely, 2^{19867526643397} is an apocalyptic number.

It is an amenable number.

19867526643397 is a deficient number, since it is larger than the sum of its proper divisors (1).

19867526643397 is an equidigital number, since it uses as much as digits as its factorization.

19867526643397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2469035520, while the sum is 76.

The spelling of 19867526643397 in words is "nineteen trillion, eight hundred sixty-seven billion, five hundred twenty-six million, six hundred forty-three thousand, three hundred ninety-seven".