21021212331 has 48 divisors (see below), whose sum is σ = 35121715200. Its totient is φ = 11867373504.

The previous prime is 21021212297. The next prime is 21021212357. The reversal of 21021212331 is 13321212012.

21021212331 is a `hidden beast` number, since 210 + 2 + 121 + 2 + 331 = 666.

It is not a de Polignac number, because 21021212331 - 2⁹ = 21021211819 is a prime.

It is a super-3 number, since 3×21021212331³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21021212371) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2460990 + ... + 2469516.

It is an arithmetic number, because the mean of its divisors is an integer number (731702400).

Almost surely, 2^21021212331 is an apocalyptic number.

21021212331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21021212331 is a deficient number, since it is larger than the sum of its proper divisors (14100502869).

21021212331 is a wasteful number, since it uses less digits than its factorization.

21021212331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9008 (or 9005 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21021212331 its reverse (13321212012), we get a palindrome (34342424343).

The spelling of 21021212331 in words is "twenty-one billion, twenty-one million, two hundred twelve thousand, three hundred thirty-one".