21000241391 has 2 divisors, whose sum is σ = 21000241392. Its totient is φ = 21000241390.

The previous prime is 21000241387. The next prime is 21000241403. The reversal of 21000241391 is 19314200012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21000241391 - 2² = 21000241387 is a prime.

It is a super-2 number, since 2×21000241391² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000241331) 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, 10500120695 + 10500120696.

It is an arithmetic number, because the mean of its divisors is an integer number (10500120696).

Almost surely, 2^21000241391 is an apocalyptic number.

21000241391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000241391 is an equidigital number, since it uses as much as digits as its factorization.

21000241391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

The spelling of 21000241391 in words is "twenty-one billion, two hundred forty-one thousand, three hundred ninety-one".