21740628 has 96 divisors (see below), whose sum is σ = 64024576. Its totient is φ = 5588352.

The previous prime is 21740627. The next prime is 21740639. The reversal of 21740628 is 82604712.

It is a junction number, because it is equal to n+sod(n) for n = 21740595 and 21740604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21740623) 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 31 ways as a sum of consecutive naturals, for example, 46725 + ... + 47187.

Almost surely, 2^21740628 is an apocalyptic number.

21740628 is a gapful number since it is divisible by the number (28) 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 21740628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32012288).

21740628 is an abundant number, since it is smaller than the sum of its proper divisors (42283948).

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

21740628 is a wasteful number, since it uses less digits than its factorization.

21740628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533 (or 531 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21740628 is about 4662.6846344140. The cubic root of 21740628 is about 279.0984095493.

The spelling of 21740628 in words is "twenty-one million, seven hundred forty thousand, six hundred twenty-eight".