21042552 has 32 divisors (see below), whose sum is σ = 54305280. Its totient is φ = 6787680.

The previous prime is 21042551. The next prime is 21042563. The reversal of 21042552 is 25524012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042551) 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, 13398 + ... + 14885.

It is an arithmetic number, because the mean of its divisors is an integer number (1697040).

Almost surely, 2^21042552 is an apocalyptic number.

It is an amenable number.

21042552 is an abundant number, since it is smaller than the sum of its proper divisors (33262728).

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

21042552 is a wasteful number, since it uses less digits than its factorization.

21042552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28323 (or 28319 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 21042552 is about 4587.2161492565. The cubic root of 21042552 is about 276.0786375380.

Adding to 21042552 its reverse (25524012), we get a palindrome (46566564).

It can be divided in two parts, 2104 and 2552, that added together give a triangular number (4656 = T₉₆).

The spelling of 21042552 in words is "twenty-one million, forty-two thousand, five hundred fifty-two".