21457349 has 8 divisors (see below), whose sum is σ = 22946328. Its totient is φ = 19993600.

The previous prime is 21457339. The next prime is 21457379. The reversal of 21457349 is 94375412.

It can be written as a sum of positive squares in 4 ways, for example, as 12124324 + 9333025 = 3482^2 + 3055^2 .

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 21457349 - 2¹² = 21453253 is a prime.

It is a super-2 number, since 2×21457349² = 920835652215602, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21457339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4532 + ... + 7965.

It is an arithmetic number, because the mean of its divisors is an integer number (2868291).

Almost surely, 2^21457349 is an apocalyptic number.

It is an amenable number.

21457349 is a deficient number, since it is larger than the sum of its proper divisors (1488979).

21457349 is a wasteful number, since it uses less digits than its factorization.

21457349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12615.

The product of its digits is 30240, while the sum is 35.

The square root of 21457349 is about 4632.2077889490. The cubic root of 21457349 is about 277.8808945814.

The spelling of 21457349 in words is "twenty-one million, four hundred fifty-seven thousand, three hundred forty-nine".