21228460 has 24 divisors (see below), whose sum is σ = 48632976. Its totient is φ = 7719360.

The previous prime is 21228451. The next prime is 21228469. The reversal of 21228460 is 6482212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21228451) and next prime (21228469).

It is a super-3 number, since 3×21228460³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21228469) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48027 + ... + 48466.

It is an arithmetic number, because the mean of its divisors is an integer number (2026374).

Almost surely, 2^21228460 is an apocalyptic number.

21228460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21228460 is an abundant number, since it is smaller than the sum of its proper divisors (27404516).

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

21228460 is a wasteful number, since it uses less digits than its factorization.

21228460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96513 (or 96511 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21228460 is about 4607.4352952592. The cubic root of 21228460 is about 276.8892935600.

The spelling of 21228460 in words is "twenty-one million, two hundred twenty-eight thousand, four hundred sixty".