20121100021 has 8 divisors (see below), whose sum is σ = 21952826784. Its totient is φ = 18289795920.

The previous prime is 20121100003. The next prime is 20121100079. The reversal of 20121100021 is 12000112102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20121100021 - 2¹⁷ = 20120968949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121099980 and 20121100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121103021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1666 + ... + 200611.

It is an arithmetic number, because the mean of its divisors is an integer number (2744103348).

Almost surely, 2^20121100021 is an apocalyptic number.

It is an amenable number.

20121100021 is a deficient number, since it is larger than the sum of its proper divisors (1831726763).

20121100021 is a wasteful number, since it uses less digits than its factorization.

20121100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211331.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20121100021 its reverse (12000112102), we get a palindrome (32121212123).

The spelling of 20121100021 in words is "twenty billion, one hundred twenty-one million, one hundred thousand, twenty-one".