21859920369 has 12 divisors (see below), whose sum is σ = 36086217856. Its totient is φ = 12491383032.

The previous prime is 21859920367. The next prime is 21859920371. The reversal of 21859920369 is 96302995812.

It is a happy number.

21859920369 is a `hidden beast` number, since 2 + 18 + 599 + 2 + 0 + 36 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (21859920367) and next prime (21859920371).

It is not a de Polignac number, because 21859920369 - 2¹ = 21859920367 is a prime.

It is a super-2 number, since 2×21859920369² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21859920367) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173491369 + ... + 173491494.

Almost surely, 2^21859920369 is an apocalyptic number.

It is an amenable number.

21859920369 is a deficient number, since it is larger than the sum of its proper divisors (14226297487).

21859920369 is a wasteful number, since it uses less digits than its factorization.

21859920369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346982876 (or 346982873 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 54.

The spelling of 21859920369 in words is "twenty-one billion, eight hundred fifty-nine million, nine hundred twenty thousand, three hundred sixty-nine".