21635941 has 2 divisors, whose sum is σ = 21635942. Its totient is φ = 21635940.

The previous prime is 21635921. The next prime is 21635969. The reversal of 21635941 is 14953612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21585316 + 50625 = 4646^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 21635941 - 2²¹ = 19538789 is a prime.

It is a super-2 number, since 2×21635941² = 936227885910962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21635921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10817970 + 10817971.

It is an arithmetic number, because the mean of its divisors is an integer number (10817971).

Almost surely, 2^21635941 is an apocalyptic number.

It is an amenable number.

21635941 is a deficient number, since it is larger than the sum of its proper divisors (1).

21635941 is an equidigital number, since it uses as much as digits as its factorization.

21635941 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 21635941 is about 4651.4450442846. The cubic root of 21635941 is about 278.6497104815.

The spelling of 21635941 in words is "twenty-one million, six hundred thirty-five thousand, nine hundred forty-one".