21212278989 has 32 divisors (see below), whose sum is σ = 32763626496. Its totient is φ = 12064715520.

The previous prime is 21212278943. The next prime is 21212278991. The reversal of 21212278989 is 98987221212.

It is not a de Polignac number, because 21212278989 - 2¹² = 21212274893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212278289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140184 + ... + 249150.

It is an arithmetic number, because the mean of its divisors is an integer number (1023863328).

Almost surely, 2^21212278989 is an apocalyptic number.

It is an amenable number.

21212278989 is a deficient number, since it is larger than the sum of its proper divisors (11551347507).

21212278989 is a wasteful number, since it uses less digits than its factorization.

21212278989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109345.

The product of its digits is 580608, while the sum is 51.

The spelling of 21212278989 in words is "twenty-one billion, two hundred twelve million, two hundred seventy-eight thousand, nine hundred eighty-nine".