21147456 has 224 divisors, whose sum is σ = 70225920. Its totient is φ = 5529600.

The previous prime is 21147433. The next prime is 21147479. The reversal of 21147456 is 65474112.

It is an interprime number because it is at equal distance from previous prime (21147433) and next prime (21147479).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 682161 + ... + 682191.

Almost surely, 2^21147456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21147456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35112960).

21147456 is an abundant number, since it is smaller than the sum of its proper divisors (49078464).

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

21147456 is a wasteful number, since it uses less digits than its factorization.

21147456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 83 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21147456 is about 4598.6363196061. The cubic root of 21147456 is about 276.5366580023.

The spelling of 21147456 in words is "twenty-one million, one hundred forty-seven thousand, four hundred fifty-six".