20420232421 has 2 divisors, whose sum is σ = 20420232422. Its totient is φ = 20420232420.

The previous prime is 20420232389. The next prime is 20420232493. The reversal of 20420232421 is 12423202402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20023665025 + 396567396 = 141505^2 + 19914^2 .

It is a cyclic number.

It is not a de Polignac number, because 20420232421 - 2⁵ = 20420232389 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20420232392 and 20420232401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20420232221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210116210 + 10210116211.

It is an arithmetic number, because the mean of its divisors is an integer number (10210116211).

Almost surely, 2^20420232421 is an apocalyptic number.

It is an amenable number.

20420232421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20420232421 is an equidigital number, since it uses as much as digits as its factorization.

20420232421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 20420232421 its reverse (12423202402), we get a palindrome (32843434823).

The spelling of 20420232421 in words is "twenty billion, four hundred twenty million, two hundred thirty-two thousand, four hundred twenty-one".