21542413 has 2 divisors, whose sum is σ = 21542414. Its totient is φ = 21542412.

The previous prime is 21542393. The next prime is 21542453. The reversal of 21542413 is 31424512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19474569 + 2067844 = 4413^2 + 1438^2 .

It is a cyclic number.

It is not a de Polignac number, because 21542413 - 2⁹ = 21541901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21542453) 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, 10771206 + 10771207.

It is an arithmetic number, because the mean of its divisors is an integer number (10771207).

Almost surely, 2^21542413 is an apocalyptic number.

It is an amenable number.

21542413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21542413 is an equidigital number, since it uses as much as digits as its factorization.

21542413 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 22.

The square root of 21542413 is about 4641.3805058409. The cubic root of 21542413 is about 278.2476142106.

Adding to 21542413 its reverse (31424512), we get a palindrome (52966925).

The spelling of 21542413 in words is "twenty-one million, five hundred forty-two thousand, four hundred thirteen".