2121292781 has 2 divisors, whose sum is σ = 2121292782. Its totient is φ = 2121292780.

The previous prime is 2121292763. The next prime is 2121292787. The reversal of 2121292781 is 1872921212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1353504100 + 767788681 = 36790^2 + 27709^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121292781 - 2⁶ = 2121292717 is a prime.

It is a super-2 number, since 2×2121292781² = 8999766125445427922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121292787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060646390 + 1060646391.

It is an arithmetic number, because the mean of its divisors is an integer number (1060646391).

Almost surely, 2^2121292781 is an apocalyptic number.

It is an amenable number.

2121292781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121292781 is an equidigital number, since it uses as much as digits as its factorization.

2121292781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 2121292781 is about 46057.4942978882. The cubic root of 2121292781 is about 1284.8927284574.

The spelling of 2121292781 in words is "two billion, one hundred twenty-one million, two hundred ninety-two thousand, seven hundred eighty-one".