21554680 has 64 divisors (see below), whose sum is σ = 57853440. Its totient is φ = 7066752.

The previous prime is 21554671. The next prime is 21554681. The reversal of 21554680 is 8645512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4767 + ... + 8113.

It is an arithmetic number, because the mean of its divisors is an integer number (903960).

Almost surely, 2^21554680 is an apocalyptic number.

21554680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21554680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28926720).

21554680 is an abundant number, since it is smaller than the sum of its proper divisors (36298760).

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

21554680 is a wasteful number, since it uses less digits than its factorization.

21554680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3388 (or 3384 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 21554680 is about 4642.7017995990. The cubic root of 21554680 is about 278.3004188153.

The spelling of 21554680 in words is "twenty-one million, five hundred fifty-four thousand, six hundred eighty".