19678758961 has 3 divisors (see below), whose sum is σ = 19678899243. Its totient is φ = 19678618680.

The previous prime is 19678758959. The next prime is 19678758977. The reversal of 19678758961 is 16985787691.

It is a happy number.

The square root of 19678758961 is 140281.

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., 15918616561 + 3760142400 = 126169^2 + 61320^2 .

It is not a de Polignac number, because 19678758961 - 2¹ = 19678758959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19678758941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 70141 + ... + 210421.

It is an arithmetic number, because the mean of its divisors is an integer number (6559633081).

Almost surely, 2^19678758961 is an apocalyptic number.

19678758961 is the 140281-st square number.

19678758961 is the 70141-st centered octagonal number.

It is an amenable number.

19678758961 is a deficient number, since it is larger than the sum of its proper divisors (140282).

19678758961 is an frugal number, since it uses more digits than its factorization.

19678758961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280562 (or 140281 counting only the distinct ones).

The product of its digits is 45722880, while the sum is 67.

It can be divided in two parts, 1967875 and 8961, that added together give a square (1976836 = 1406²).

The spelling of 19678758961 in words is "nineteen billion, six hundred seventy-eight million, seven hundred fifty-eight thousand, nine hundred sixty-one".