20987951983 has 8 divisors (see below), whose sum is σ = 21207552800. Its totient is φ = 20768417280.

The previous prime is 20987951981. The next prime is 20987952047. The reversal of 20987951983 is 38915978902.

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 20987951983 - 2¹ = 20987951981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20987951981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 865798 + ... + 889708.

It is an arithmetic number, because the mean of its divisors is an integer number (2650944100).

Almost surely, 2^20987951983 is an apocalyptic number.

20987951983 is a deficient number, since it is larger than the sum of its proper divisors (219600817).

20987951983 is an equidigital number, since it uses as much as digits as its factorization.

20987951983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33057.

The product of its (nonzero) digits is 9797760, while the sum is 61.

The spelling of 20987951983 in words is "twenty billion, nine hundred eighty-seven million, nine hundred fifty-one thousand, nine hundred eighty-three".