21402313 has 4 divisors (see below), whose sum is σ = 21591828. Its totient is φ = 21212800.

The previous prime is 21402299. The next prime is 21402323. The reversal of 21402313 is 31320412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 944784 + 20457529 = 972^2 + 4523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21402313 - 2⁵ = 21402281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21402323) 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 3 ways as a sum of consecutive naturals, for example, 94588 + ... + 94813.

It is an arithmetic number, because the mean of its divisors is an integer number (5397957).

Almost surely, 2^21402313 is an apocalyptic number.

It is an amenable number.

21402313 is a deficient number, since it is larger than the sum of its proper divisors (189515).

21402313 is a wasteful number, since it uses less digits than its factorization.

21402313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189514.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21402313 is about 4626.2633950090. The cubic root of 21402313 is about 277.6431120703.

Adding to 21402313 its reverse (31320412), we get a palindrome (52722725).

The spelling of 21402313 in words is "twenty-one million, four hundred two thousand, three hundred thirteen".