21451456 has 112 divisors (see below), whose sum is σ = 51206400. Its totient is φ = 8819712.

The previous prime is 21451439. The next prime is 21451459. The reversal of 21451456 is 65415412.

It is not an unprimeable number, because it can be changed into a prime (21451459) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 363555 + ... + 363613.

It is an arithmetic number, because the mean of its divisors is an integer number (457200).

Almost surely, 2^21451456 is an apocalyptic number.

21451456 is a gapful number since it is divisible by the number (26) 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 21451456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25603200).

21451456 is an abundant number, since it is smaller than the sum of its proper divisors (29754944).

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

21451456 is a wasteful number, since it uses less digits than its factorization.

21451456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 116 counting only the distinct ones).

The product of its digits is 4800, while the sum is 28.

The square root of 21451456 is about 4631.5716554967. The cubic root of 21451456 is about 277.8554533826.

Adding to 21451456 its reverse (65415412), we get a palindrome (86866868).

The spelling of 21451456 in words is "twenty-one million, four hundred fifty-one thousand, four hundred fifty-six".