21201779985 has 32 divisors (see below), whose sum is σ = 34773604992. Its totient is φ = 11024401920.

The previous prime is 21201779953. The next prime is 21201780001. The reversal of 21201779985 is 58997710212.

It is not a de Polignac number, because 21201779985 - 2⁵ = 21201779953 is a prime.

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, 971362 + ... + 992948.

It is an arithmetic number, because the mean of its divisors is an integer number (1086675156).

Almost surely, 2^21201779985 is an apocalyptic number.

It is an amenable number.

21201779985 is a deficient number, since it is larger than the sum of its proper divisors (13571825007).

21201779985 is a wasteful number, since it uses less digits than its factorization.

21201779985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23233.

The product of its (nonzero) digits is 635040, while the sum is 51.

The spelling of 21201779985 in words is "twenty-one billion, two hundred one million, seven hundred seventy-nine thousand, nine hundred eighty-five".