20021211987 has 12 divisors (see below), whose sum is σ = 31053308616. Its totient is φ = 11440692480.

The previous prime is 20021211979. The next prime is 20021211989. The reversal of 20021211987 is 78911212002.

It is not a de Polignac number, because 20021211987 - 2³ = 20021211979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20021211989) 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 11 ways as a sum of consecutive naturals, for example, 68099214 + ... + 68099507.

It is an arithmetic number, because the mean of its divisors is an integer number (2587775718).

Almost surely, 2^20021211987 is an apocalyptic number.

20021211987 is a deficient number, since it is larger than the sum of its proper divisors (11032096629).

20021211987 is a wasteful number, since it uses less digits than its factorization.

20021211987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136198738 (or 136198731 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 33.

Adding to 20021211987 its reverse (78911212002), we get a palindrome (98932423989).

The spelling of 20021211987 in words is "twenty billion, twenty-one million, two hundred eleven thousand, nine hundred eighty-seven".