20657987985 has 8 divisors (see below), whose sum is σ = 33052780800. Its totient is φ = 11017593584.

The previous prime is 20657987969. The next prime is 20657988059. The reversal of 20657987985 is 58978975602.

It is a happy number.

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 20657987985 - 2⁴ = 20657987969 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 688599585 + ... + 688599614.

It is an arithmetic number, because the mean of its divisors is an integer number (4131597600).

Almost surely, 2^20657987985 is an apocalyptic number.

It is an amenable number.

20657987985 is a deficient number, since it is larger than the sum of its proper divisors (12394792815).

20657987985 is a wasteful number, since it uses less digits than its factorization.

20657987985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1377199207.

The product of its (nonzero) digits is 76204800, while the sum is 66.

The spelling of 20657987985 in words is "twenty billion, six hundred fifty-seven million, nine hundred eighty-seven thousand, nine hundred eighty-five".