21121659986 has 16 divisors (see below), whose sum is σ = 36274767936. Its totient is φ = 9035588016.

The previous prime is 21121659971. The next prime is 21121659997. The reversal of 21121659986 is 68995612112.

It is a super-2 number, since 2×21121659986² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1371401 + ... + 1386716.

It is an arithmetic number, because the mean of its divisors is an integer number (2267172996).

Almost surely, 2^21121659986 is an apocalyptic number.

21121659986 is a deficient number, since it is larger than the sum of its proper divisors (15153107950).

21121659986 is a wasteful number, since it uses less digits than its factorization.

21121659986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2758673.

The product of its digits is 466560, while the sum is 50.

The spelling of 21121659986 in words is "twenty-one billion, one hundred twenty-one million, six hundred fifty-nine thousand, nine hundred eighty-six".