21220311996 has 72 divisors (see below), whose sum is σ = 57842504720. Its totient is φ = 6520725504.

The previous prime is 21220311977. The next prime is 21220312007. The reversal of 21220311996 is 69911302212.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21220311996.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 330411 + ... + 389373.

Almost surely, 2^21220311996 is an apocalyptic number.

21220311996 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21220311996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28921252360).

21220311996 is an abundant number, since it is smaller than the sum of its proper divisors (36622192724).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21220311996 is a wasteful number, since it uses less digits than its factorization.

21220311996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59755 (or 59750 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The spelling of 21220311996 in words is "twenty-one billion, two hundred twenty million, three hundred eleven thousand, nine hundred ninety-six".