21554028 has 72 divisors (see below), whose sum is σ = 59164560. Its totient is φ = 6589440.

The previous prime is 21553997. The next prime is 21554033. The reversal of 21554028 is 82045512.

It is a happy number.

It is a super-2 number, since 2×21554028² = 929152246049568, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21553992 and 21554010.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24663 + ... + 25521.

It is an arithmetic number, because the mean of its divisors is an integer number (821730).

Almost surely, 2^21554028 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 21554028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29582280).

21554028 is an abundant number, since it is smaller than the sum of its proper divisors (37610532).

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

21554028 is a wasteful number, since it uses less digits than its factorization.

21554028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 927 (or 922 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 21554028 is about 4642.6315813340. The cubic root of 21554028 is about 278.2976127162.

The spelling of 21554028 in words is "twenty-one million, five hundred fifty-four thousand, twenty-eight".