21487441 has 2 divisors, whose sum is σ = 21487442. Its totient is φ = 21487440.

The previous prime is 21487429. The next prime is 21487469. The reversal of 21487441 is 14478412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13535041 + 7952400 = 3679^2 + 2820^2 .

It is a cyclic number.

It is not a de Polignac number, because 21487441 - 2⁵ = 21487409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21487421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10743720 + 10743721.

It is an arithmetic number, because the mean of its divisors is an integer number (10743721).

Almost surely, 2^21487441 is an apocalyptic number.

It is an amenable number.

21487441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21487441 is an equidigital number, since it uses as much as digits as its factorization.

21487441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7168, while the sum is 31.

The square root of 21487441 is about 4635.4547781205. The cubic root of 21487441 is about 278.0107348821.

The spelling of 21487441 in words is "twenty-one million, four hundred eighty-seven thousand, four hundred forty-one".