21020061239 has 2 divisors, whose sum is σ = 21020061240. Its totient is φ = 21020061238.

The previous prime is 21020061203. The next prime is 21020061287. The reversal of 21020061239 is 93216002012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020061239 - 2⁸ = 21020060983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020061289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510030619 + 10510030620.

It is an arithmetic number, because the mean of its divisors is an integer number (10510030620).

Almost surely, 2^21020061239 is an apocalyptic number.

21020061239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020061239 is an equidigital number, since it uses as much as digits as its factorization.

21020061239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The spelling of 21020061239 in words is "twenty-one billion, twenty million, sixty-one thousand, two hundred thirty-nine".