21547442 has 8 divisors (see below), whose sum is σ = 36938496. Its totient is φ = 9234612.

The previous prime is 21547439. The next prime is 21547451. The reversal of 21547442 is 24474512.

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 769538 + ... + 769565.

It is an arithmetic number, because the mean of its divisors is an integer number (4617312).

Almost surely, 2^21547442 is an apocalyptic number.

21547442 is a deficient number, since it is larger than the sum of its proper divisors (15391054).

21547442 is a wasteful number, since it uses less digits than its factorization.

21547442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1539112.

The product of its digits is 8960, while the sum is 29.

The square root of 21547442 is about 4641.9222311452. The cubic root of 21547442 is about 278.2692644992.

The spelling of 21547442 in words is "twenty-one million, five hundred forty-seven thousand, four hundred forty-two".