21021331331 has 24 divisors (see below), whose sum is σ = 28438281312. Its totient is φ = 15120230400.

The previous prime is 21021331327. The next prime is 21021331337. The reversal of 21021331331 is 13313312012.

It is not a de Polignac number, because 21021331331 - 2² = 21021331327 is a prime.

It is a super-2 number, since 2×21021331331² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21021331337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 943550 + ... + 965571.

It is an arithmetic number, because the mean of its divisors is an integer number (1184928388).

Almost surely, 2^21021331331 is an apocalyptic number.

21021331331 is a deficient number, since it is larger than the sum of its proper divisors (7416949981).

21021331331 is a wasteful number, since it uses less digits than its factorization.

21021331331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909163 (or 1909152 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21021331331 its reverse (13313312012), we get a palindrome (34334643343).

The spelling of 21021331331 in words is "twenty-one billion, twenty-one million, three hundred thirty-one thousand, three hundred thirty-one".