21420210407 has 2 divisors, whose sum is σ = 21420210408. Its totient is φ = 21420210406.

The previous prime is 21420210373. The next prime is 21420210433. The reversal of 21420210407 is 70401202412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21420210407 - 2³² = 17125243111 is a prime.

It is a super-2 number, since 2×21420210407² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21420200407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710105203 + 10710105204.

It is an arithmetic number, because the mean of its divisors is an integer number (10710105204).

Almost surely, 2^21420210407 is an apocalyptic number.

21420210407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420210407 is an equidigital number, since it uses as much as digits as its factorization.

21420210407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 23.

Adding to 21420210407 its reverse (70401202412), we get a palindrome (91821412819).

The spelling of 21420210407 in words is "twenty-one billion, four hundred twenty million, two hundred ten thousand, four hundred seven".