21451128 has 16 divisors (see below), whose sum is σ = 53627880. Its totient is φ = 7150368.

The previous prime is 21451121. The next prime is 21451139. The reversal of 21451128 is 82115412.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 893797 = 21451128 / (2 + 1 + 4 + 5 + 1 + 1 + 2 + 8).

It is a junction number, because it is equal to n+sod(n) for n = 21451098 and 21451107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 446875 + ... + 446922.

Almost surely, 2^21451128 is an apocalyptic number.

It is an amenable number.

21451128 is an abundant number, since it is smaller than the sum of its proper divisors (32176752).

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

21451128 is a wasteful number, since it uses less digits than its factorization.

21451128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 893806 (or 893802 counting only the distinct ones).

The product of its digits is 640, while the sum is 24.

The square root of 21451128 is about 4631.5362462146. The cubic root of 21451128 is about 277.8540372075.

The spelling of 21451128 in words is "twenty-one million, four hundred fifty-one thousand, one hundred twenty-eight".