21013312329 has 10 divisors (see below), whose sum is σ = 31390256810. Its totient is φ = 14008874832.

The previous prime is 21013312303. The next prime is 21013312339. The reversal of 21013312329 is 92321331012.

21013312329 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 331 + 2 + 329 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17436674304 + 3576638025 = 132048^2 + 59805^2 .

It is not a de Polignac number, because 21013312329 - 2²¹ = 21011215177 is a prime.

It is a super-2 number, since 2×21013312329² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21013312339) 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 9 ways as a sum of consecutive naturals, for example, 129711724 + ... + 129711885.

It is an arithmetic number, because the mean of its divisors is an integer number (3139025681).

Almost surely, 2^21013312329 is an apocalyptic number.

It is an amenable number.

21013312329 is a deficient number, since it is larger than the sum of its proper divisors (10376944481).

21013312329 is an equidigital number, since it uses as much as digits as its factorization.

21013312329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259423621 (or 259423612 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The spelling of 21013312329 in words is "twenty-one billion, thirteen million, three hundred twelve thousand, three hundred twenty-nine".