21309381369 has 32 divisors (see below), whose sum is σ = 33382702080. Its totient is φ = 13412649600.

The previous prime is 21309381367. The next prime is 21309381413. The reversal of 21309381369 is 96318390312.

It is not a de Polignac number, because 21309381369 - 2¹ = 21309381367 is a prime.

It is a super-2 number, since 2×21309381369² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21309381367) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 276162 + ... + 344795.

It is an arithmetic number, because the mean of its divisors is an integer number (1043209440).

Almost surely, 2^21309381369 is an apocalyptic number.

It is an amenable number.

21309381369 is a deficient number, since it is larger than the sum of its proper divisors (12073320711).

21309381369 is a wasteful number, since it uses less digits than its factorization.

21309381369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621038 (or 621032 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The spelling of 21309381369 in words is "twenty-one billion, three hundred nine million, three hundred eighty-one thousand, three hundred sixty-nine".