21102985787 has 16 divisors (see below), whose sum is σ = 23527160832. Its totient is φ = 18796851360.

The previous prime is 21102985747. The next prime is 21102985793. The reversal of 21102985787 is 78758920112.

It is a cyclic number.

It is not a de Polignac number, because 21102985787 - 2⁶ = 21102985723 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21102985747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64388 + ... + 215294.

It is an arithmetic number, because the mean of its divisors is an integer number (1470447552).

Almost surely, 2^21102985787 is an apocalyptic number.

21102985787 is a deficient number, since it is larger than the sum of its proper divisors (2424175045).

21102985787 is a wasteful number, since it uses less digits than its factorization.

21102985787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151298.

The product of its (nonzero) digits is 564480, while the sum is 50.

The spelling of 21102985787 in words is "twenty-one billion, one hundred two million, nine hundred eighty-five thousand, seven hundred eighty-seven".