20999552 has 64 divisors (see below), whose sum is σ = 49939200. Its totient is φ = 8600064.

The previous prime is 20999551. The next prime is 20999593. The reversal of 20999552 is 25599902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999551) 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, 20099 + ... + 21117.

It is an arithmetic number, because the mean of its divisors is an integer number (780300).

Almost surely, 2^20999552 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 20999552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24969600).

20999552 is an abundant number, since it is smaller than the sum of its proper divisors (28939648).

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

20999552 is a wasteful number, since it uses less digits than its factorization.

20999552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1063 (or 1051 counting only the distinct ones).

The product of its (nonzero) digits is 72900, while the sum is 41.

The square root of 20999552 is about 4582.5268138877. The cubic root of 20999552 is about 275.8904557225.

The spelling of 20999552 in words is "twenty million, nine hundred ninety-nine thousand, five hundred fifty-two".