21542452 has 6 divisors (see below), whose sum is σ = 37699298. Its totient is φ = 10771224.

The previous prime is 21542413. The next prime is 21542453. The reversal of 21542452 is 25424512.

It can be written as a sum of positive squares in only one way, i.e., 18352656 + 3189796 = 4284^2 + 1786^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a 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, 2692803 + ... + 2692810.

Almost surely, 2^21542452 is an apocalyptic number.

It is an amenable number.

21542452 is a deficient number, since it is larger than the sum of its proper divisors (16156846).

21542452 is a wasteful number, since it uses less digits than its factorization.

21542452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5385617 (or 5385615 counting only the distinct ones).

The product of its digits is 3200, while the sum is 25.

The square root of 21542452 is about 4641.3847071752. The cubic root of 21542452 is about 278.2477821220.

Adding to 21542452 its reverse (25424512), we get a palindrome (46966964).

The spelling of 21542452 in words is "twenty-one million, five hundred forty-two thousand, four hundred fifty-two".