21202423481 has 2 divisors, whose sum is σ = 21202423482. Its totient is φ = 21202423480.

The previous prime is 21202423423. The next prime is 21202423499. The reversal of 21202423481 is 18432420212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11211421456 + 9991002025 = 105884^2 + 99955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202423481 is a prime.

It is a super-2 number, since 2×21202423481² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21202423381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601211740 + 10601211741.

It is an arithmetic number, because the mean of its divisors is an integer number (10601211741).

Almost surely, 2^21202423481 is an apocalyptic number.

It is an amenable number.

21202423481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202423481 is an equidigital number, since it uses as much as digits as its factorization.

21202423481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6144, while the sum is 29.

Adding to 21202423481 its reverse (18432420212), we get a palindrome (39634843693).

The spelling of 21202423481 in words is "twenty-one billion, two hundred two million, four hundred twenty-three thousand, four hundred eighty-one".