21580242 has 16 divisors (see below), whose sum is σ = 45699552. Its totient is φ = 6770240.

The previous prime is 21580217. The next prime is 21580243. The reversal of 21580242 is 24208512.

It is not an unprimeable number, because it can be changed into a prime (21580243) 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 7 ways as a sum of consecutive naturals, for example, 105684 + ... + 105887.

It is an arithmetic number, because the mean of its divisors is an integer number (2856222).

Almost surely, 2^21580242 is an apocalyptic number.

21580242 is an abundant number, since it is smaller than the sum of its proper divisors (24119310).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21580242 is a wasteful number, since it uses less digits than its factorization.

21580242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211593.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21580242 is about 4645.4539067781. The cubic root of 21580242 is about 278.4103888233.

Adding to 21580242 its reverse (24208512), we get a palindrome (45788754).

The spelling of 21580242 in words is "twenty-one million, five hundred eighty thousand, two hundred forty-two".