20129535681 has 8 divisors (see below), whose sum is σ = 26954572320. Its totient is φ = 13362094752.

The previous prime is 20129535667. The next prime is 20129535719. The reversal of 20129535681 is 18653592102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20129535681 - 2⁹ = 20129535169 is a prime.

It is a super-2 number, since 2×20129535681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20129535641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14398111 + ... + 14399508.

It is an arithmetic number, because the mean of its divisors is an integer number (3369321540).

Almost surely, 2^20129535681 is an apocalyptic number.

It is an amenable number.

20129535681 is a deficient number, since it is larger than the sum of its proper divisors (6825036639).

20129535681 is a wasteful number, since it uses less digits than its factorization.

20129535681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28797855.

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 20129535681 in words is "twenty billion, one hundred twenty-nine million, five hundred thirty-five thousand, six hundred eighty-one".