21426876649 has 2 divisors, whose sum is σ = 21426876650. Its totient is φ = 21426876648.

The previous prime is 21426876637. The next prime is 21426876739. The reversal of 21426876649 is 94667862412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18362147049 + 3064729600 = 135507^2 + 55360^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426876649 - 2¹⁵ = 21426843881 is a prime.

It is a super-2 number, since 2×21426876649² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21426876649.

It is not a weakly prime, because it can be changed into another prime (21426871649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713438324 + 10713438325.

It is an arithmetic number, because the mean of its divisors is an integer number (10713438325).

Almost surely, 2^21426876649 is an apocalyptic number.

It is an amenable number.

21426876649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426876649 is an equidigital number, since it uses as much as digits as its factorization.

21426876649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6967296, while the sum is 55.

The spelling of 21426876649 in words is "twenty-one billion, four hundred twenty-six million, eight hundred seventy-six thousand, six hundred forty-nine".