21121444 has 6 divisors (see below), whose sum is σ = 36962534. Its totient is φ = 10560720.

The previous prime is 21121417. The next prime is 21121453. The reversal of 21121444 is 44412112.

It can be written as a sum of positive squares in only one way, i.e., 18593344 + 2528100 = 4312^2 + 1590^2 .

It is a super-3 number, since 3×21121444³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640177 + ... + 2640184.

Almost surely, 2^21121444 is an apocalyptic number.

It is an amenable number.

21121444 is a deficient number, since it is larger than the sum of its proper divisors (15841090).

21121444 is a wasteful number, since it uses less digits than its factorization.

21121444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280365 (or 5280363 counting only the distinct ones).

The product of its digits is 256, while the sum is 19.

The square root of 21121444 is about 4595.8072196296. The cubic root of 21121444 is about 276.4232287104.

Adding to 21121444 its reverse (44412112), we get a palindrome (65533556).

The spelling of 21121444 in words is "twenty-one million, one hundred twenty-one thousand, four hundred forty-four".