21242350313 has 4 divisors (see below), whose sum is σ = 21430335828. Its totient is φ = 21054364800.

The previous prime is 21242350307. The next prime is 21242350351. The reversal of 21242350313 is 31305324212.

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 8778190864 + 12464159449 = 93692^2 + 111643^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242350313 - 2⁶ = 21242350249 is a prime.

It is a super-2 number, since 2×21242350313² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21242353313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93992588 + ... + 93992813.

It is an arithmetic number, because the mean of its divisors is an integer number (5357583957).

Almost surely, 2^21242350313 is an apocalyptic number.

It is an amenable number.

21242350313 is a deficient number, since it is larger than the sum of its proper divisors (187985515).

21242350313 is a wasteful number, since it uses less digits than its factorization.

21242350313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187985514.

The product of its (nonzero) digits is 4320, while the sum is 26.

Adding to 21242350313 its reverse (31305324212), we get a palindrome (52547674525).

The spelling of 21242350313 in words is "twenty-one billion, two hundred forty-two million, three hundred fifty thousand, three hundred thirteen".