21385542 has 8 divisors (see below), whose sum is σ = 42771096. Its totient is φ = 7128512.

The previous prime is 21385513. The next prime is 21385549. The reversal of 21385542 is 24558312.

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

21385542 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385549) 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, 1782123 + ... + 1782134.

It is an arithmetic number, because the mean of its divisors is an integer number (5346387).

Almost surely, 2^21385542 is an apocalyptic number.

21385542 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21385542 is a wasteful number, since it uses less digits than its factorization.

21385542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3564262.

The product of its digits is 9600, while the sum is 30.

The square root of 21385542 is about 4624.4504538377. The cubic root of 21385542 is about 277.5705721005.

The spelling of 21385542 in words is "twenty-one million, three hundred eighty-five thousand, five hundred forty-two".