21788149329 has 6 divisors (see below), whose sum is σ = 31471771266. Its totient is φ = 14525432880.

The previous prime is 21788149307. The next prime is 21788149349. The reversal of 21788149329 is 92394188712.

21788149329 is a `hidden beast` number, since 2 + 1 + 78 + 81 + 493 + 2 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17238377025 + 4549772304 = 131295^2 + 67452^2 .

It is not a de Polignac number, because 21788149329 - 2⁸ = 21788149073 is a prime.

It is a super-3 number, since 3×21788149329³ (a number of 32 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21788149349) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1210452732 + ... + 1210452749.

It is an arithmetic number, because the mean of its divisors is an integer number (5245295211).

Almost surely, 2^21788149329 is an apocalyptic number.

It is an amenable number.

21788149329 is a deficient number, since it is larger than the sum of its proper divisors (9683621937).

21788149329 is a wasteful number, since it uses less digits than its factorization.

21788149329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2420905487 (or 2420905484 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The spelling of 21788149329 in words is "twenty-one billion, seven hundred eighty-eight million, one hundred forty-nine thousand, three hundred twenty-nine".