21013961911 has 4 divisors (see below), whose sum is σ = 21014422792. Its totient is φ = 21013501032.

The previous prime is 21013961873. The next prime is 21013961921. The reversal of 21013961911 is 11916931012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21013961911 - 2¹⁷ = 21013830839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013961921) 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 in 3 ways as a sum of consecutive naturals, for example, 153480 + ... + 256093.

It is an arithmetic number, because the mean of its divisors is an integer number (5253605698).

Almost surely, 2^21013961911 is an apocalyptic number.

21013961911 is a deficient number, since it is larger than the sum of its proper divisors (460881).

21013961911 is an equidigital number, since it uses as much as digits as its factorization.

21013961911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460880.

The product of its (nonzero) digits is 2916, while the sum is 34.

The spelling of 21013961911 in words is "twenty-one billion, thirteen million, nine hundred sixty-one thousand, nine hundred eleven".