21351460 has 36 divisors (see below), whose sum is σ = 48560148. Its totient is φ = 7882368.

The previous prime is 21351457. The next prime is 21351469. The reversal of 21351460 is 6415312.

It can be written as a sum of positive squares in 6 ways, for example, as 3912484 + 17438976 = 1978^2 + 4176^2 .

It is not an unprimeable number, because it can be changed into a prime (21351469) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222 + ... + 6538.

It is an arithmetic number, because the mean of its divisors is an integer number (1348893).

Almost surely, 2^21351460 is an apocalyptic number.

21351460 is a gapful number since it is divisible by the number (20) 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 21351460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24280074).

21351460 is an abundant number, since it is smaller than the sum of its proper divisors (27208688).

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

21351460 is a wasteful number, since it uses less digits than its factorization.

21351460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6352 (or 6337 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21351460 is about 4620.7640060925. The cubic root of 21351460 is about 277.4230395569.

Adding to 21351460 its reverse (6415312), we get a palindrome (27766772).

The spelling of 21351460 in words is "twenty-one million, three hundred fifty-one thousand, four hundred sixty".