21540842 has 8 divisors (see below), whose sum is σ = 32381856. Its totient is φ = 10746892.

The previous prime is 21540833. The next prime is 21540847. The reversal of 21540842 is 24804512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21540847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10598 + ... + 12465.

It is an arithmetic number, because the mean of its divisors is an integer number (4047732).

Almost surely, 2^21540842 is an apocalyptic number.

21540842 is a deficient number, since it is larger than the sum of its proper divisors (10841014).

21540842 is a wasteful number, since it uses less digits than its factorization.

21540842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23532.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 21540842 is about 4641.2112643145. The cubic root of 21540842 is about 278.2408502263.

The spelling of 21540842 in words is "twenty-one million, five hundred forty thousand, eight hundred forty-two".