21212123020 has 48 divisors (see below), whose sum is σ = 49076235936. Its totient is φ = 7637120000.

The previous prime is 21212123003. The next prime is 21212123021. The reversal of 21212123020 is 2032121212.

It is a happy number.

It is a super-2 number, since 2×21212123020² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212122985 and 21212123003.

It is not an unprimeable number, because it can be changed into a prime (21212123021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 455101 + ... + 499540.

It is an arithmetic number, because the mean of its divisors is an integer number (1022421582).

Almost surely, 2^21212123020 is an apocalyptic number.

21212123020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212123020 is an abundant number, since it is smaller than the sum of its proper divisors (27864112916).

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

21212123020 is a wasteful number, since it uses less digits than its factorization.

21212123020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954762 (or 954760 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21212123020 its reverse (2032121212), we get a palindrome (23244244232).

The spelling of 21212123020 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-three thousand, twenty".