20021120021 has 32 divisors (see below), whose sum is σ = 25231872000. Its totient is φ = 15498205632.

The previous prime is 20021119973. The next prime is 20021120027. The reversal of 20021120021 is 12002112002.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-20021120021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021119984 and 20021120011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021120027) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 271850 + ... + 337556.

It is an arithmetic number, because the mean of its divisors is an integer number (788496000).

Almost surely, 2^20021120021 is an apocalyptic number.

It is an amenable number.

20021120021 is a deficient number, since it is larger than the sum of its proper divisors (5210751979).

20021120021 is a wasteful number, since it uses less digits than its factorization.

20021120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65841.

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

Adding to 20021120021 its reverse (12002112002), we get a palindrome (32023232023).

The spelling of 20021120021 in words is "twenty billion, twenty-one million, one hundred twenty thousand, twenty-one".