21342481 has 2 divisors, whose sum is σ = 21342482. Its totient is φ = 21342480.

The previous prime is 21342479. The next prime is 21342487. The reversal of 21342481 is 18424312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11451456 + 9891025 = 3384^2 + 3145^2 .

It is a cyclic number.

It is not a de Polignac number, because 21342481 - 2¹ = 21342479 is a prime.

It is a super-2 number, since 2×21342481² = 911002990470722, which contains 22 as substring.

Together with 21342479, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21342487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10671240 + 10671241.

It is an arithmetic number, because the mean of its divisors is an integer number (10671241).

Almost surely, 2^21342481 is an apocalyptic number.

It is an amenable number.

21342481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21342481 is an equidigital number, since it uses as much as digits as its factorization.

21342481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 25.

The square root of 21342481 is about 4619.7923113491. The cubic root of 21342481 is about 277.3841455619.

Adding to 21342481 its reverse (18424312), we get a palindrome (39766793).

The spelling of 21342481 in words is "twenty-one million, three hundred forty-two thousand, four hundred eighty-one".