21693552 has 80 divisors (see below), whose sum is σ = 59043840. Its totient is φ = 6854400.

The previous prime is 21693527. The next prime is 21693557. The reversal of 21693552 is 25539612.

It is a super-2 number, since 2×21693552² = 941220396753408, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21693557) 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, 90649 + ... + 90887.

It is an arithmetic number, because the mean of its divisors is an integer number (738048).

Almost surely, 2^21693552 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 21693552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29521920).

21693552 is an abundant number, since it is smaller than the sum of its proper divisors (37350288).

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

21693552 is a wasteful number, since it uses less digits than its factorization.

21693552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 336 counting only the distinct ones).

The product of its digits is 16200, while the sum is 33.

The square root of 21693552 is about 4657.6337339898. The cubic root of 21693552 is about 278.8968156865.

The spelling of 21693552 in words is "twenty-one million, six hundred ninety-three thousand, five hundred fifty-two".