21310144 has 56 divisors (see below), whose sum is σ = 45646848. Its totient is φ = 9841920.

The previous prime is 21310141. The next prime is 21310147. The reversal of 21310144 is 44101312.

It is an interprime number because it is at equal distance from previous prime (21310141) and next prime (21310147).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (21310141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45399 + ... + 45865.

Almost surely, 2^21310144 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 21310144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22823424).

21310144 is an abundant number, since it is smaller than the sum of its proper divisors (24336704).

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

21310144 is a wasteful number, since it uses less digits than its factorization.

21310144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533 (or 523 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21310144 is about 4616.2911519964. The cubic root of 21310144 is about 277.2439821463.

Adding to 21310144 its reverse (44101312), we get a palindrome (65411456).

The spelling of 21310144 in words is "twenty-one million, three hundred ten thousand, one hundred forty-four".