21699552 has 96 divisors (see below), whose sum is σ = 66528000. Its totient is φ = 6190464.

The previous prime is 21699533. The next prime is 21699553. The reversal of 21699552 is 25599612.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 21699552.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21699553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32599 + ... + 33257.

It is an arithmetic number, because the mean of its divisors is an integer number (693000).

Almost surely, 2^21699552 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 21699552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33264000).

21699552 is an abundant number, since it is smaller than the sum of its proper divisors (44828448).

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

21699552 is an equidigital number, since it uses as much as digits as its factorization.

21699552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693 (or 671 counting only the distinct ones).

The product of its digits is 48600, while the sum is 39.

The square root of 21699552 is about 4658.2777933481. The cubic root of 21699552 is about 278.9225257322.

The spelling of 21699552 in words is "twenty-one million, six hundred ninety-nine thousand, five hundred fifty-two".