19173663961 has 3 divisors (see below), whose sum is σ = 19173802431. Its totient is φ = 19173525492.

The previous prime is 19173663919. The next prime is 19173663967. The reversal of 19173663961 is 16936637191.

The square root of 19173663961 is 138469.

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 can be written as a sum of positive squares in only one way, i.e., 7392732361 + 11780931600 = 85981^2 + 108540^2 .

It is not a de Polignac number, because 19173663961 - 2⁹ = 19173663449 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19173663899 and 19173663908.

It is not an unprimeable number, because it can be changed into a prime (19173663967) 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, 69235 + ... + 207703.

It is an arithmetic number, because the mean of its divisors is an integer number (6391267477).

Almost surely, 2^19173663961 is an apocalyptic number.

19173663961 is the 138469-th square number.

19173663961 is the 69235-th centered octagonal number.

It is an amenable number.

19173663961 is a deficient number, since it is larger than the sum of its proper divisors (138470).

19173663961 is an frugal number, since it uses more digits than its factorization.

19173663961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276938 (or 138469 counting only the distinct ones).

The product of its digits is 1102248, while the sum is 52.

The spelling of 19173663961 in words is "nineteen billion, one hundred seventy-three million, six hundred sixty-three thousand, nine hundred sixty-one".