21070944 has 72 divisors (see below), whose sum is σ = 62545392. Its totient is φ = 6716160.

The previous prime is 21070937. The next prime is 21070949. The reversal of 21070944 is 44907012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×21070944² = 887969362102272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21070949) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 5034 + ... + 8214.

It is an arithmetic number, because the mean of its divisors is an integer number (868686).

Almost surely, 2^21070944 is an apocalyptic number.

21070944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21070944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31272696).

21070944 is an abundant number, since it is smaller than the sum of its proper divisors (41474448).

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

21070944 is a wasteful number, since it uses less digits than its factorization.

21070944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3220 (or 3209 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21070944 is about 4590.3097934671. The cubic root of 21070944 is about 276.2027495744.

Adding to 21070944 its reverse (44907012), we get a palindrome (65977956).

The spelling of 21070944 in words is "twenty-one million, seventy thousand, nine hundred forty-four".