21544402 has 8 divisors (see below), whose sum is σ = 35254512. Its totient is φ = 9792900.

The previous prime is 21544373. The next prime is 21544403. The reversal of 21544402 is 20444512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21544402² = 928322515075208, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22), and also a Moran number because the ratio is a prime number: 979291 = 21544402 / (2 + 1 + 5 + 4 + 4 + 4 + 0 + 2).

It is not an unprimeable number, because it can be changed into a prime (21544403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 489624 + ... + 489667.

It is an arithmetic number, because the mean of its divisors is an integer number (4406814).

Almost surely, 2^21544402 is an apocalyptic number.

21544402 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21544402 is a deficient number, since it is larger than the sum of its proper divisors (13710110).

21544402 is a wasteful number, since it uses less digits than its factorization.

21544402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 979304.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21544402 is about 4641.5947690422. The cubic root of 21544402 is about 278.2561774338.

Adding to 21544402 its reverse (20444512), we get a palindrome (41988914).

It can be divided in two parts, 2154 and 4402, that added together give a palindrome (6556).

The spelling of 21544402 in words is "twenty-one million, five hundred forty-four thousand, four hundred two".