20421201023 has 4 divisors (see below), whose sum is σ = 21622448160. Its totient is φ = 19219953888.

The previous prime is 20421200981. The next prime is 20421201041. The reversal of 20421201023 is 32010212402.

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 20421201023 - 2⁶ = 20421200959 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1201247119 = 20421201023 / (2 + 0 + 4 + 2 + 1 + 2 + 0 + 1 + 0 + 2 + 3).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20421200992 and 20421201010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421201523) 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, 600623543 + ... + 600623576.

It is an arithmetic number, because the mean of its divisors is an integer number (5405612040).

Almost surely, 2^20421201023 is an apocalyptic number.

20421201023 is a deficient number, since it is larger than the sum of its proper divisors (1201247137).

20421201023 is a wasteful number, since it uses less digits than its factorization.

20421201023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201247136.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 20421201023 its reverse (32010212402), we get a palindrome (52431413425).

The spelling of 20421201023 in words is "twenty billion, four hundred twenty-one million, two hundred one thousand, twenty-three".