21198811986 has 48 divisors (see below), whose sum is σ = 50116049568. Its totient is φ = 6422630400.

The previous prime is 21198811979. The next prime is 21198811987. The reversal of 21198811986 is 68911889112.

It is not an unprimeable number, because it can be changed into a prime (21198811987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1794130 + ... + 1805906.

It is an arithmetic number, because the mean of its divisors is an integer number (1044084366).

Almost surely, 2^21198811986 is an apocalyptic number.

21198811986 is an abundant number, since it is smaller than the sum of its proper divisors (28917237582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21198811986 is a wasteful number, since it uses less digits than its factorization.

21198811986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20887 (or 20884 counting only the distinct ones).

The product of its digits is 497664, while the sum is 54.

The spelling of 21198811986 in words is "twenty-one billion, one hundred ninety-eight million, eight hundred eleven thousand, nine hundred eighty-six".