20665961971 has 8 divisors (see below), whose sum is σ = 21761160080. Its totient is φ = 19571515488.

The previous prime is 20665961969. The next prime is 20665962007. The reversal of 20665961971 is 17916956602.

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

It is a cyclic number.

It is not a de Polignac number, because 20665961971 - 2¹ = 20665961969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665361971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131016 + ... + 241861.

It is an arithmetic number, because the mean of its divisors is an integer number (2720145010).

Almost surely, 2^20665961971 is an apocalyptic number.

20665961971 is a deficient number, since it is larger than the sum of its proper divisors (1095198109).

20665961971 is a wasteful number, since it uses less digits than its factorization.

20665961971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375813.

The product of its (nonzero) digits is 1224720, while the sum is 52.

The spelling of 20665961971 in words is "twenty billion, six hundred sixty-five million, nine hundred sixty-one thousand, nine hundred seventy-one".