21254464 has 112 divisors (see below), whose sum is σ = 55595520. Its totient is φ = 7810560.

The previous prime is 21254459. The next prime is 21254491. The reversal of 21254464 is 46445212.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93519 + ... + 93745.

Almost surely, 2^21254464 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 21254464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27797760).

21254464 is an abundant number, since it is smaller than the sum of its proper divisors (34341056).

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

21254464 is a wasteful number, since it uses less digits than its factorization.

21254464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 266 counting only the distinct ones).

The product of its digits is 7680, while the sum is 28.

The square root of 21254464 is about 4610.2563920025. The cubic root of 21254464 is about 277.0023068009.

Adding to 21254464 its reverse (46445212), we get a palindrome (67699676).

The spelling of 21254464 in words is "twenty-one million, two hundred fifty-four thousand, four hundred sixty-four".