21121320139 has 2 divisors, whose sum is σ = 21121320140. Its totient is φ = 21121320138.

The previous prime is 21121320097. The next prime is 21121320203. The reversal of 21121320139 is 93102312112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121320139 - 2¹¹ = 21121318091 is a prime.

It is a super-2 number, since 2×21121320139² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121320839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560660069 + 10560660070.

It is an arithmetic number, because the mean of its divisors is an integer number (10560660070).

Almost surely, 2^21121320139 is an apocalyptic number.

21121320139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121320139 is an equidigital number, since it uses as much as digits as its factorization.

21121320139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The spelling of 21121320139 in words is "twenty-one billion, one hundred twenty-one million, three hundred twenty thousand, one hundred thirty-nine".