1926638978881 has 2 divisors, whose sum is σ = 1926638978882. Its totient is φ = 1926638978880.

The previous prime is 1926638978851. The next prime is 1926638978903. The reversal of 1926638978881 is 1888798366291.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1627193628225 + 299445350656 = 1275615^2 + 547216^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1926638978881 is a prime.

It is a super-2 number, since 2×1926638978881² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1926638978798 and 1926638978807.

It is not a weakly prime, because it can be changed into another prime (1926638978801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 963319489440 + 963319489441.

It is an arithmetic number, because the mean of its divisors is an integer number (963319489441).

Almost surely, 2^{1926638978881} is an apocalyptic number.

It is an amenable number.

1926638978881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1926638978881 is an equidigital number, since it uses as much as digits as its factorization.

1926638978881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 501645312, while the sum is 76.

The spelling of 1926638978881 in words is "one trillion, nine hundred twenty-six billion, six hundred thirty-eight million, nine hundred seventy-eight thousand, eight hundred eighty-one".