21011121020220 has 48 divisors (see below), whose sum is σ = 58884768155808. Its totient is φ = 5597858053120.

The previous prime is 21011121020147. The next prime is 21011121020251. The reversal of 21011121020220 is 2202012111012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21011121020220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159544641 + ... + 159676280.

It is an arithmetic number, because the mean of its divisors is an integer number (1226766003246).

Almost surely, 2^{21011121020220} is an apocalyptic number.

21011121020220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011121020220 is an abundant number, since it is smaller than the sum of its proper divisors (37873647135588).

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

21011121020220 is a wasteful number, since it uses less digits than its factorization.

21011121020220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319222030 (or 319222028 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21011121020220 its reverse (2202012111012), we get a palindrome (23213133131232).

The spelling of 21011121020220 in words is "twenty-one trillion, eleven billion, one hundred twenty-one million, twenty thousand, two hundred twenty".