21278095985 has 16 divisors (see below), whose sum is σ = 27039142656. Its totient is φ = 16019113728.

The previous prime is 21278095981. The next prime is 21278095997. The reversal of 21278095985 is 58959087212.

It is a cyclic number.

It is not a de Polignac number, because 21278095985 - 2² = 21278095981 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21278095985.

It is not an unprimeable number, because it can be changed into a prime (21278095981) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1178234 + ... + 1196156.

It is an arithmetic number, because the mean of its divisors is an integer number (1689946416).

Almost surely, 2^21278095985 is an apocalyptic number.

It is an amenable number.

21278095985 is a deficient number, since it is larger than the sum of its proper divisors (5761046671).

21278095985 is a wasteful number, since it uses less digits than its factorization.

21278095985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31912.

The product of its (nonzero) digits is 3628800, while the sum is 56.

The spelling of 21278095985 in words is "twenty-one billion, two hundred seventy-eight million, ninety-five thousand, nine hundred eighty-five".