21031199985 has 32 divisors (see below), whose sum is σ = 33757430400. Its totient is φ = 11180868608.

The previous prime is 21031199947. The next prime is 21031199993. The reversal of 21031199985 is 58999113012.

It is a cyclic number.

It is not a de Polignac number, because 21031199985 - 2⁷ = 21031199857 is a prime.

It is a super-2 number, since 2×21031199985² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8249491 + ... + 8252039.

It is an arithmetic number, because the mean of its divisors is an integer number (1054919700).

Almost surely, 2^21031199985 is an apocalyptic number.

It is an amenable number.

21031199985 is a deficient number, since it is larger than the sum of its proper divisors (12726230415).

21031199985 is a wasteful number, since it uses less digits than its factorization.

21031199985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4097.

The product of its (nonzero) digits is 174960, while the sum is 48.

The spelling of 21031199985 in words is "twenty-one billion, thirty-one million, one hundred ninety-nine thousand, nine hundred eighty-five".