21012021311 has 4 divisors (see below), whose sum is σ = 21736573800. Its totient is φ = 20287468824.

The previous prime is 21012021293. The next prime is 21012021313. The reversal of 21012021311 is 11312021012.

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 21012021311 - 2²² = 21007827007 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 (21012021313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 362276201 + ... + 362276258.

It is an arithmetic number, because the mean of its divisors is an integer number (5434143450).

Almost surely, 2^21012021311 is an apocalyptic number.

21012021311 is a deficient number, since it is larger than the sum of its proper divisors (724552489).

21012021311 is an equidigital number, since it uses as much as digits as its factorization.

21012021311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724552488.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21012021311 its reverse (11312021012), we get a palindrome (32324042323).

The spelling of 21012021311 in words is "twenty-one billion, twelve million, twenty-one thousand, three hundred eleven".