21307441 has 2 divisors, whose sum is σ = 21307442. Its totient is φ = 21307440.

The previous prime is 21307423. The next prime is 21307457. The reversal of 21307441 is 14470312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21298225 + 9216 = 4615^2 + 96^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21307441 is a prime.

It is not a weakly prime, because it can be changed into another prime (21307411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653720 + 10653721.

It is an arithmetic number, because the mean of its divisors is an integer number (10653721).

Almost surely, 2^21307441 is an apocalyptic number.

It is an amenable number.

21307441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21307441 is an equidigital number, since it uses as much as digits as its factorization.

21307441 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21307441 is about 4615.9983752164. The cubic root of 21307441 is about 277.2322596825.

Adding to 21307441 its reverse (14470312), we get a palindrome (35777753).

The spelling of 21307441 in words is "twenty-one million, three hundred seven thousand, four hundred forty-one".