20980621961 has 8 divisors (see below), whose sum is σ = 23923605384. Its totient is φ = 18227508480.

The previous prime is 20980621957. The next prime is 20980622009. The reversal of 20980621961 is 16912608902.

It can be written as a sum of positive squares in 4 ways, for example, as 3444736 + 20977177225 = 1856^2 + 144835^2 .

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 20980621961 - 2² = 20980621957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20980621901) 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, 47467250 + ... + 47467691.

It is an arithmetic number, because the mean of its divisors is an integer number (2990450673).

Almost surely, 2^20980621961 is an apocalyptic number.

It is an amenable number.

20980621961 is a deficient number, since it is larger than the sum of its proper divisors (2942983423).

20980621961 is a wasteful number, since it uses less digits than its factorization.

20980621961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94934971.

The product of its (nonzero) digits is 93312, while the sum is 44.

The spelling of 20980621961 in words is "twenty billion, nine hundred eighty million, six hundred twenty-one thousand, nine hundred sixty-one".