21279552 has 112 divisors (see below), whose sum is σ = 65544192. Its totient is φ = 5967360.

The previous prime is 21279527. The next prime is 21279571. The reversal of 21279552 is 25597212.

It is a happy number.

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

It is a super-3 number, since 3×21279552³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95313 + ... + 95535.

It is an arithmetic number, because the mean of its divisors is an integer number (585216).

Almost surely, 2^21279552 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 21279552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32772096).

21279552 is an abundant number, since it is smaller than the sum of its proper divisors (44264640).

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

21279552 is a wasteful number, since it uses less digits than its factorization.

21279552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 306 counting only the distinct ones).

The product of its digits is 12600, while the sum is 33.

The square root of 21279552 is about 4612.9764794545. The cubic root of 21279552 is about 277.1112517795. Note that the first 3 decimals are identical.

The spelling of 21279552 in words is "twenty-one million, two hundred seventy-nine thousand, five hundred fifty-two".