20688981291 has 24 divisors (see below), whose sum is σ = 32682999024. Its totient is φ = 12507168960.

The previous prime is 20688981253. The next prime is 20688981293. The reversal of 20688981291 is 19218988602.

It is not a de Polignac number, because 20688981291 - 2⁷ = 20688981163 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20688981293) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 223896 + ... + 302501.

It is an arithmetic number, because the mean of its divisors is an integer number (1361791626).

Almost surely, 2^20688981291 is an apocalyptic number.

20688981291 is a deficient number, since it is larger than the sum of its proper divisors (11994017733).

20688981291 is a wasteful number, since it uses less digits than its factorization.

20688981291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526811 (or 526808 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 54.

The spelling of 20688981291 in words is "twenty billion, six hundred eighty-eight million, nine hundred eighty-one thousand, two hundred ninety-one".