21868787890 has 16 divisors (see below), whose sum is σ = 39365501760. Its totient is φ = 8747141040.

The previous prime is 21868787869. The next prime is 21868787891. The reversal of 21868787890 is 9878786812.

It is not an unprimeable number, because it can be changed into a prime (21868787891) 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 7 ways as a sum of consecutive naturals, for example, 441181 + ... + 488239.

It is an arithmetic number, because the mean of its divisors is an integer number (2460343860).

Almost surely, 2^21868787890 is an apocalyptic number.

21868787890 is a deficient number, since it is larger than the sum of its proper divisors (17496713870).

21868787890 is a wasteful number, since it uses less digits than its factorization.

21868787890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93537.

The product of its (nonzero) digits is 21676032, while the sum is 64.

The spelling of 21868787890 in words is "twenty-one billion, eight hundred sixty-eight million, seven hundred eighty-seven thousand, eight hundred ninety".