21313405 has 8 divisors (see below), whose sum is σ = 26458200. Its totient is φ = 16462656.

The previous prime is 21313379. The next prime is 21313429. The reversal of 21313405 is 50431312.

It can be written as a sum of positive squares in 4 ways, for example, as 910116 + 20403289 = 954^2 + 4517^2 .

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 21313405 - 2⁵ = 21313373 is a prime.

It is a super-2 number, since 2×21313405² = 908522465388050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73350 + ... + 73639.

It is an arithmetic number, because the mean of its divisors is an integer number (3307275).

Almost surely, 2^21313405 is an apocalyptic number.

It is an amenable number.

21313405 is a deficient number, since it is larger than the sum of its proper divisors (5144795).

21313405 is a wasteful number, since it uses less digits than its factorization.

21313405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147023.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21313405 is about 4616.6443441097. The cubic root of 21313405 is about 277.2581232444.

Adding to 21313405 its reverse (50431312), we get a palindrome (71744717).

The spelling of 21313405 in words is "twenty-one million, three hundred thirteen thousand, four hundred five".