21430512 has 60 divisors (see below), whose sum is σ = 61388184. Its totient is φ = 6975360.

The previous prime is 21430481. The next prime is 21430529. The reversal of 21430512 is 21503412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4462 + ... + 7922.

Almost surely, 2^21430512 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 21430512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30694092).

21430512 is an abundant number, since it is smaller than the sum of its proper divisors (39957672).

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

21430512 is a wasteful number, since it uses less digits than its factorization.

21430512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3518 (or 3509 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21430512 is about 4629.3100997881. The cubic root of 21430512 is about 277.7649964371.

Adding to 21430512 its reverse (21503412), we get a palindrome (42933924).

Subtracting 21430512 from its reverse (21503412), we obtain a square (72900 = 270²).

The spelling of 21430512 in words is "twenty-one million, four hundred thirty thousand, five hundred twelve".