20011220028 has 72 divisors (see below), whose sum is σ = 50873462640. Its totient is φ = 6632317440.

The previous prime is 20011220027. The next prime is 20011220029. The reversal of 20011220028 is 82002211002.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20011220027) and next prime (20011220029).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011220027) 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 23 ways as a sum of consecutive naturals, for example, 7173658 + ... + 7176446.

It is an arithmetic number, because the mean of its divisors is an integer number (706575870).

Almost surely, 2^20011220028 is an apocalyptic number.

It is an amenable number.

20011220028 is an abundant number, since it is smaller than the sum of its proper divisors (30862242612).

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

20011220028 is a wasteful number, since it uses less digits than its factorization.

20011220028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3867 (or 3862 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The spelling of 20011220028 in words is "twenty billion, eleven million, two hundred twenty thousand, twenty-eight".