21640141 has 2 divisors, whose sum is σ = 21640142. Its totient is φ = 21640140.

The previous prime is 21640127. The next prime is 21640147. The reversal of 21640141 is 14104612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16892100 + 4748041 = 4110^2 + 2179^2 .

It is a cyclic number.

It is not a de Polignac number, because 21640141 - 2⁷ = 21640013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21640147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10820070 + 10820071.

It is an arithmetic number, because the mean of its divisors is an integer number (10820071).

Almost surely, 2^21640141 is an apocalyptic number.

It is an amenable number.

21640141 is a deficient number, since it is larger than the sum of its proper divisors (1).

21640141 is an equidigital number, since it uses as much as digits as its factorization.

21640141 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21640141 is about 4651.8964949792. The cubic root of 21640141 is about 278.6677399426.

Adding to 21640141 its reverse (14104612), we get a palindrome (35744753).

The spelling of 21640141 in words is "twenty-one million, six hundred forty thousand, one hundred forty-one".