21420013331 has 2 divisors, whose sum is σ = 21420013332. Its totient is φ = 21420013330.

The previous prime is 21420013313. The next prime is 21420013357. The reversal of 21420013331 is 13331002412.

Together with previous prime (21420013313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21420013331 - 2³⁰ = 20346271507 is a prime.

It is a super-2 number, since 2×21420013331² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21420018331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710006665 + 10710006666.

It is an arithmetic number, because the mean of its divisors is an integer number (10710006666).

Almost surely, 2^21420013331 is an apocalyptic number.

21420013331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420013331 is an equidigital number, since it uses as much as digits as its factorization.

21420013331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21420013331 its reverse (13331002412), we get a palindrome (34751015743).

The spelling of 21420013331 in words is "twenty-one billion, four hundred twenty million, thirteen thousand, three hundred thirty-one".