21304542 has 32 divisors (see below), whose sum is σ = 48960000. Its totient is φ = 6054048.

The previous prime is 21304537. The next prime is 21304561. The reversal of 21304542 is 24540312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7084 + ... + 9632.

It is an arithmetic number, because the mean of its divisors is an integer number (1530000).

Almost surely, 2^21304542 is an apocalyptic number.

21304542 is an abundant number, since it is smaller than the sum of its proper divisors (27655458).

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

21304542 is a wasteful number, since it uses less digits than its factorization.

21304542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2760.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21304542 is about 4615.6843479597. The cubic root of 21304542 is about 277.2196860974.

Adding to 21304542 its reverse (24540312), we get a palindrome (45844854).

The spelling of 21304542 in words is "twenty-one million, three hundred four thousand, five hundred forty-two".