21210999988 has 12 divisors (see below), whose sum is σ = 37144912672. Its totient is φ = 10598167800.

The previous prime is 21210999973. The next prime is 21210999989. The reversal of 21210999988 is 88999901212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210999989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1826538 + ... + 1838113.

Almost surely, 2^21210999988 is an apocalyptic number.

It is an amenable number.

21210999988 is a deficient number, since it is larger than the sum of its proper divisors (15933912684).

21210999988 is a wasteful number, since it uses less digits than its factorization.

21210999988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3666102 (or 3666100 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 58.

The spelling of 21210999988 in words is "twenty-one billion, two hundred ten million, nine hundred ninety-nine thousand, nine hundred eighty-eight".