21510642289 has 2 divisors, whose sum is σ = 21510642290. Its totient is φ = 21510642288.

The previous prime is 21510642277. The next prime is 21510642343. The reversal of 21510642289 is 98224601512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16936419600 + 4574222689 = 130140^2 + 67633^2 .

It is a cyclic number.

It is not a de Polignac number, because 21510642289 - 2¹³ = 21510634097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21510642239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755321144 + 10755321145.

It is an arithmetic number, because the mean of its divisors is an integer number (10755321145).

Almost surely, 2^21510642289 is an apocalyptic number.

It is an amenable number.

21510642289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510642289 is an equidigital number, since it uses as much as digits as its factorization.

21510642289 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 40.

The spelling of 21510642289 in words is "twenty-one billion, five hundred ten million, six hundred forty-two thousand, two hundred eighty-nine".