21002012122120 has 16 divisors (see below), whose sum is σ = 47254527274860. Its totient is φ = 8400804848832.

The previous prime is 21002012122103. The next prime is 21002012122127. The reversal of 21002012122120 is 2122121020012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18754633358244 + 2247378763876 = 4330662^2 + 1499126^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21002012122094 and 21002012122103.

It is not an unprimeable number, because it can be changed into a prime (21002012122127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 262525151487 + ... + 262525151566.

Almost surely, 2^{21002012122120} is an apocalyptic number.

21002012122120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002012122120 is an abundant number, since it is smaller than the sum of its proper divisors (26252515152740).

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

21002012122120 is a wasteful number, since it uses less digits than its factorization.

21002012122120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525050303064 (or 525050303060 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21002012122120 its reverse (2122121020012), we get a palindrome (23124133142132).

The spelling of 21002012122120 in words is "twenty-one trillion, two billion, twelve million, one hundred twenty-two thousand, one hundred twenty".