21321542 has 16 divisors (see below), whose sum is σ = 35117712. Its totient is φ = 9628320.

The previous prime is 21321539. The next prime is 21321551. The reversal of 21321542 is 24512312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 368 + ... + 6540.

It is an arithmetic number, because the mean of its divisors is an integer number (2194857).

Almost surely, 2^21321542 is an apocalyptic number.

21321542 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21321542 is a deficient number, since it is larger than the sum of its proper divisors (13796170).

21321542 is a wasteful number, since it uses less digits than its factorization.

21321542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6343.

The product of its digits is 480, while the sum is 20.

The square root of 21321542 is about 4617.5255278125. The cubic root of 21321542 is about 277.2934024862.

Adding to 21321542 its reverse (24512312), we get a palindrome (45833854).

The spelling of 21321542 in words is "twenty-one million, three hundred twenty-one thousand, five hundred forty-two".