2126973781 has 2 divisors, whose sum is σ = 2126973782. Its totient is φ = 2126973780.

The previous prime is 2126973773. The next prime is 2126973787. The reversal of 2126973781 is 1873796212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1353577681 + 773396100 = 36791^2 + 27810^2 .

It is a cyclic number.

It is not a de Polignac number, because 2126973781 - 2³ = 2126973773 is a prime.

It is a super-2 number, since 2×2126973781² = 9048034930122871922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2126973787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1063486890 + 1063486891.

It is an arithmetic number, because the mean of its divisors is an integer number (1063486891).

Almost surely, 2^2126973781 is an apocalyptic number.

It is an amenable number.

2126973781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2126973781 is an equidigital number, since it uses as much as digits as its factorization.

2126973781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 2126973781 is about 46119.1259782750. The cubic root of 2126973781 is about 1286.0387228765.

The spelling of 2126973781 in words is "two billion, one hundred twenty-six million, nine hundred seventy-three thousand, seven hundred eighty-one".