19121634961 has 27 divisors (see below), whose sum is σ = 22782691323. Its totient is φ = 16029533520.

The previous prime is 19121634953. The next prime is 19121634971. The reversal of 19121634961 is 16943612191.

The square root of 19121634961 is 138281.

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

It can be written as a sum of positive squares in only one way, i.e., 2828644225 + 16292990736 = 53185^2 + 127644^2 .

It is not a de Polignac number, because 19121634961 - 2³ = 19121634953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19121634911) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 19773700 + ... + 19774666.

Almost surely, 2^19121634961 is an apocalyptic number.

19121634961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19121634961 is the 138281-st square number.

19121634961 is the 69141-st centered octagonal number.

It is an amenable number.

19121634961 is a deficient number, since it is larger than the sum of its proper divisors (3661056362).

19121634961 is an frugal number, since it uses more digits than its factorization.

19121634961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1982 (or 991 counting only the distinct ones).

The product of its digits is 69984, while the sum is 43.

The spelling of 19121634961 in words is "nineteen billion, one hundred twenty-one million, six hundred thirty-four thousand, nine hundred sixty-one".