21451457 has 8 divisors (see below), whose sum is σ = 21857376. Its totient is φ = 21048192.

The previous prime is 21451439. The next prime is 21451459. The reversal of 21451457 is 75415412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21451457 - 2⁸ = 21451201 is a prime.

It is a Duffinian number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23198 + ... + 24104.

It is an arithmetic number, because the mean of its divisors is an integer number (2732172).

Almost surely, 2^21451457 is an apocalyptic number.

It is an amenable number.

21451457 is a deficient number, since it is larger than the sum of its proper divisors (405919).

21451457 is an equidigital number, since it uses as much as digits as its factorization.

21451457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327.

The product of its digits is 5600, while the sum is 29.

The square root of 21451457 is about 4631.5717634514. The cubic root of 21451457 is about 277.8554577001.

Adding to 21451457 its reverse (75415412), we get a palindrome (96866869).

The spelling of 21451457 in words is "twenty-one million, four hundred fifty-one thousand, four hundred fifty-seven".