20021121023 has 4 divisors (see below), whose sum is σ = 20562232440. Its totient is φ = 19480009608.

The previous prime is 20021121019. The next prime is 20021121037. The reversal of 20021121023 is 32012112002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20021121023 - 2² = 20021121019 is a prime.

It is a super-2 number, since 2×20021121023² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021120989 and 20021121007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021127023) 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, 270555653 + ... + 270555726.

It is an arithmetic number, because the mean of its divisors is an integer number (5140558110).

Almost surely, 2^20021121023 is an apocalyptic number.

20021121023 is a deficient number, since it is larger than the sum of its proper divisors (541111417).

20021121023 is an equidigital number, since it uses as much as digits as its factorization.

20021121023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541111416.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 20021121023 its reverse (32012112002), we get a palindrome (52033233025).

The spelling of 20021121023 in words is "twenty billion, twenty-one million, one hundred twenty-one thousand, twenty-three".