21371907369 has 4 divisors (see below), whose sum is σ = 28495876496. Its totient is φ = 14247938244.

The previous prime is 21371907247. The next prime is 21371907371. The reversal of 21371907369 is 96370917312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21371907369 - 2¹⁷ = 21371776297 is a prime.

It is a super-2 number, since 2×21371907369² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21371907379) 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, 3561984559 + ... + 3561984564.

It is an arithmetic number, because the mean of its divisors is an integer number (7123969124).

Almost surely, 2^21371907369 is an apocalyptic number.

It is an amenable number.

21371907369 is a deficient number, since it is larger than the sum of its proper divisors (7123969127).

21371907369 is an equidigital number, since it uses as much as digits as its factorization.

21371907369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7123969126.

The product of its (nonzero) digits is 428652, while the sum is 48.

The spelling of 21371907369 in words is "twenty-one billion, three hundred seventy-one million, nine hundred seven thousand, three hundred sixty-nine".