21349753 has 4 divisors (see below), whose sum is σ = 21364560. Its totient is φ = 21334948.

The previous prime is 21349733. The next prime is 21349759. The reversal of 21349753 is 35794312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21349753 is a prime.

It is a super-2 number, since 2×21349753² = 911623906322018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21349759) 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 3 ways as a sum of consecutive naturals, for example, 4975 + ... + 8212.

It is an arithmetic number, because the mean of its divisors is an integer number (5341140).

Almost surely, 2^21349753 is an apocalyptic number.

It is an amenable number.

21349753 is a deficient number, since it is larger than the sum of its proper divisors (14807).

21349753 is a wasteful number, since it uses less digits than its factorization.

21349753 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14806.

The product of its digits is 22680, while the sum is 34.

The square root of 21349753 is about 4620.5792926861. The cubic root of 21349753 is about 277.4156462491.

The spelling of 21349753 in words is "twenty-one million, three hundred forty-nine thousand, seven hundred fifty-three".