21019552 has 48 divisors (see below), whose sum is σ = 43637832. Its totient is φ = 9953280.

The previous prime is 21019549. The next prime is 21019571. The reversal of 21019552 is 25591012.

It can be written as a sum of positive squares in 4 ways, for example, as 12931216 + 8088336 = 3596^2 + 2844^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48328 + ... + 48760.

Almost surely, 2^21019552 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 21019552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21818916).

21019552 is an abundant number, since it is smaller than the sum of its proper divisors (22618280).

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

21019552 is a wasteful number, since it uses less digits than its factorization.

21019552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521 (or 513 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 21019552 is about 4584.7084967313. The cubic root of 21019552 is about 275.9780140717.

The spelling of 21019552 in words is "twenty-one million, nineteen thousand, five hundred fifty-two".