19891162922401 has 3 divisors (see below), whose sum is σ = 19891167382353. Its totient is φ = 19891158462450.

The previous prime is 19891162922341. The next prime is 19891162922413. The reversal of 19891162922401 is 10422926119891.

The square root of 19891162922401 is 4459951.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 19891162922401 - 2¹¹ = 19891162920353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19891162922801) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2229976 + ... + 6689926.

It is an arithmetic number, because the mean of its divisors is an integer number (6630389127451).

Almost surely, 2^{19891162922401} is an apocalyptic number.

19891162922401 is the 4459951-st square number.

19891162922401 is the 2229976-th centered octagonal number.

It is an amenable number.

19891162922401 is a deficient number, since it is larger than the sum of its proper divisors (4459952).

19891162922401 is an frugal number, since it uses more digits than its factorization.

19891162922401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8919902 (or 4459951 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 55.

The spelling of 19891162922401 in words is "nineteen trillion, eight hundred ninety-one billion, one hundred sixty-two million, nine hundred twenty-two thousand, four hundred one".