21235233401 has 2 divisors, whose sum is σ = 21235233402. Its totient is φ = 21235233400.

The previous prime is 21235233379. The next prime is 21235233403. The reversal of 21235233401 is 10433253212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15394605625 + 5840627776 = 124075^2 + 76424^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235233401 - 2¹⁸ = 21234971257 is a prime.

Together with 21235233403, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21235233403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617616700 + 10617616701.

It is an arithmetic number, because the mean of its divisors is an integer number (10617616701).

Almost surely, 2^21235233401 is an apocalyptic number.

It is an amenable number.

21235233401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235233401 is an equidigital number, since it uses as much as digits as its factorization.

21235233401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 26.

Adding to 21235233401 its reverse (10433253212), we get a palindrome (31668486613).

The spelling of 21235233401 in words is "twenty-one billion, two hundred thirty-five million, two hundred thirty-three thousand, four hundred one".