211221000020 has 48 divisors (see below), whose sum is σ = 464111036928. Its totient is φ = 80594722560.

The previous prime is 211221000017. The next prime is 211221000037. The reversal of 211221000020 is 20000122112.

It is a happy number.

It is a super-2 number, since 2×211221000020² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211220999965 and 211221000010.

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, 456761 + ... + 794400.

It is an arithmetic number, because the mean of its divisors is an integer number (9668979936).

Almost surely, 2^211221000020 is an apocalyptic number.

211221000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

211221000020 is an abundant number, since it is smaller than the sum of its proper divisors (252890036908).

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

211221000020 is a wasteful number, since it uses less digits than its factorization.

211221000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1251560 (or 1251558 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 211221000020 its reverse (20000122112), we get a palindrome (231221122132).

The spelling of 211221000020 in words is "two hundred eleven billion, two hundred twenty-one million, twenty", and thus it is an aban number.