21047406 has 8 divisors (see below), whose sum is σ = 42094824. Its totient is φ = 7015800.

The previous prime is 21047401. The next prime is 21047407. The reversal of 21047406 is 60474012.

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

21047406 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047401) 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, 1753945 + ... + 1753956.

It is an arithmetic number, because the mean of its divisors is an integer number (5261853).

Almost surely, 2^21047406 is an apocalyptic number.

21047406 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.

21047406 is a wasteful number, since it uses less digits than its factorization.

21047406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3507906.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21047406 is about 4587.7451978069. The cubic root of 21047406 is about 276.0998640932.

The spelling of 21047406 in words is "twenty-one million, forty-seven thousand, four hundred six".