21303640345 has 16 divisors (see below), whose sum is σ = 27535510800. Its totient is φ = 15729260544.

The previous prime is 21303640333. The next prime is 21303640363. The reversal of 21303640345 is 54304630312.

It can be written as a sum of positive squares in 8 ways, for example, as 1901657664 + 19401982681 = 43608^2 + 139291^2 .

It is a cyclic number.

It is not a de Polignac number, because 21303640345 - 2¹¹ = 21303638297 is a prime.

It is a super-2 number, since 2×21303640345² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 413581 + ... + 462229.

It is an arithmetic number, because the mean of its divisors is an integer number (1720969425).

Almost surely, 2^21303640345 is an apocalyptic number.

It is an amenable number.

21303640345 is a deficient number, since it is larger than the sum of its proper divisors (6231870455).

21303640345 is a wasteful number, since it uses less digits than its factorization.

21303640345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55404.

The product of its (nonzero) digits is 25920, while the sum is 31.

The spelling of 21303640345 in words is "twenty-one billion, three hundred three million, six hundred forty thousand, three hundred forty-five".