21767608742449 has 2 divisors, whose sum is σ = 21767608742450. Its totient is φ = 21767608742448.

The previous prime is 21767608742423. The next prime is 21767608742501. The reversal of 21767608742449 is 94424780676712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14945028174400 + 6822580568049 = 3865880^2 + 2612007^2 .

It is a cyclic number.

It is not a de Polignac number, because 21767608742449 - 2¹⁷ = 21767608611377 is a prime.

It is not a weakly prime, because it can be changed into another prime (21767608772449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883804371224 + 10883804371225.

It is an arithmetic number, because the mean of its divisors is an integer number (10883804371225).

Almost surely, 2^{21767608742449} is an apocalyptic number.

It is an amenable number.

21767608742449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21767608742449 is an equidigital number, since it uses as much as digits as its factorization.

21767608742449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 227598336, while the sum is 67.

The spelling of 21767608742449 in words is "twenty-one trillion, seven hundred sixty-seven billion, six hundred eight million, seven hundred forty-two thousand, four hundred forty-nine".