20402242021 has 4 divisors (see below), whose sum is σ = 23316848032. Its totient is φ = 17487636012.

The previous prime is 20402242001. The next prime is 20402242033. The reversal of 20402242021 is 12024220402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20402242021 - 2¹¹ = 20402239973 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20402242021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20402242001) 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, 1457302995 + ... + 1457303008.

It is an arithmetic number, because the mean of its divisors is an integer number (5829212008).

Almost surely, 2^20402242021 is an apocalyptic number.

It is an amenable number.

20402242021 is a deficient number, since it is larger than the sum of its proper divisors (2914606011).

20402242021 is an equidigital number, since it uses as much as digits as its factorization.

20402242021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914606010.

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 20402242021 its reverse (12024220402), we get a palindrome (32426462423).

The spelling of 20402242021 in words is "twenty billion, four hundred two million, two hundred forty-two thousand, twenty-one".