21789708148169 has 16 divisors (see below), whose sum is σ = 23682450477840. Its totient is φ = 19927930936320.

The previous prime is 21789708148097. The next prime is 21789708148171. The reversal of 21789708148169 is 96184180798712.

It can be written as a sum of positive squares in 8 ways, for example, as 7117092812944 + 14672615335225 = 2667788^2 + 3830485^2 .

It is a cyclic number.

It is not a de Polignac number, because 21789708148169 - 2¹² = 21789708144073 is a prime.

It is a super-2 number, since 2×21789708148169² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21789708148199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25391429 + ... + 26235549.

It is an arithmetic number, because the mean of its divisors is an integer number (1480153154865).

Almost surely, 2^{21789708148169} is an apocalyptic number.

It is an amenable number.

21789708148169 is a deficient number, since it is larger than the sum of its proper divisors (1892742329671).

21789708148169 is a wasteful number, since it uses less digits than its factorization.

21789708148169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 862460.

The product of its (nonzero) digits is 97542144, while the sum is 71.

The spelling of 21789708148169 in words is "twenty-one trillion, seven hundred eighty-nine billion, seven hundred eight million, one hundred forty-eight thousand, one hundred sixty-nine".