21728050 has 12 divisors (see below), whose sum is σ = 40414266. Its totient is φ = 8691200.

The previous prime is 21728041. The next prime is 21728051. The reversal of 21728050 is 5082712.

It can be written as a sum of positive squares in 3 ways, for example, as 20493729 + 1234321 = 4527^2 + 1111^2 .

It is a super-4 number, since 4×21728050⁴ (a number of 30 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21728051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 217231 + ... + 217330.

Almost surely, 2^21728050 is an apocalyptic number.

21728050 is a deficient number, since it is larger than the sum of its proper divisors (18686216).

21728050 is a wasteful number, since it uses less digits than its factorization.

21728050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434573 (or 434568 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21728050 is about 4661.3356454990. The cubic root of 21728050 is about 279.0445752103.

The spelling of 21728050 in words is "twenty-one million, seven hundred twenty-eight thousand, fifty".