21077888 has 64 divisors (see below), whose sum is σ = 46267200. Its totient is φ = 9504768.

The previous prime is 21077887. The next prime is 21077891. The reversal of 21077888 is 88877012.

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 (21077887) 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, 88073 + ... + 88311.

It is an arithmetic number, because the mean of its divisors is an integer number (722925).

Almost surely, 2^21077888 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 21077888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23133600).

21077888 is an abundant number, since it is smaller than the sum of its proper divisors (25189312).

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

21077888 is a wasteful number, since it uses less digits than its factorization.

21077888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 50176, while the sum is 41.

The square root of 21077888 is about 4591.0661071259. The cubic root of 21077888 is about 276.2330874217.

The spelling of 21077888 in words is "twenty-one million, seventy-seven thousand, eight hundred eighty-eight".