21542211 has 12 divisors (see below), whose sum is σ = 31627440. Its totient is φ = 14125680.

The previous prime is 21542173. The next prime is 21542231. The reversal of 21542211 is 11224512.

It is not a de Polignac number, because 21542211 - 2⁷ = 21542083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21542231) 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 in 11 ways as a sum of consecutive naturals, for example, 19071 + ... + 20168.

It is an arithmetic number, because the mean of its divisors is an integer number (2635620).

Almost surely, 2^21542211 is an apocalyptic number.

21542211 is a deficient number, since it is larger than the sum of its proper divisors (10085229).

21542211 is a wasteful number, since it uses less digits than its factorization.

21542211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39306 (or 39303 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 21542211 is about 4641.3587450228. The cubic root of 21542211 is about 278.2467445123.

Adding to 21542211 its reverse (11224512), we get a palindrome (32766723).

The spelling of 21542211 in words is "twenty-one million, five hundred forty-two thousand, two hundred eleven".