20421435401 has 2 divisors, whose sum is σ = 20421435402. Its totient is φ = 20421435400.

The previous prime is 20421435341. The next prime is 20421435407. The reversal of 20421435401 is 10453412402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20420695801 + 739600 = 142901^2 + 860^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421435401 - 2¹⁴ = 20421419017 is a prime.

It is not a weakly prime, because it can be changed into another prime (20421435407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210717700 + 10210717701.

It is an arithmetic number, because the mean of its divisors is an integer number (10210717701).

Almost surely, 2^20421435401 is an apocalyptic number.

It is an amenable number.

20421435401 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421435401 is an equidigital number, since it uses as much as digits as its factorization.

20421435401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 20421435401 its reverse (10453412402), we get a palindrome (30874847803).

The spelling of 20421435401 in words is "twenty billion, four hundred twenty-one million, four hundred thirty-five thousand, four hundred one".