21550540313 has 4 divisors (see below), whose sum is σ = 21845753268. Its totient is φ = 21255327360.

The previous prime is 21550540247. The next prime is 21550540337. The reversal of 21550540313 is 31304505512.

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 15642004624 + 5908535689 = 125068^2 + 76867^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21550540313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21550540393) 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, 147606368 + ... + 147606513.

It is an arithmetic number, because the mean of its divisors is an integer number (5461438317).

Almost surely, 2^21550540313 is an apocalyptic number.

It is an amenable number.

21550540313 is a deficient number, since it is larger than the sum of its proper divisors (295212955).

21550540313 is an equidigital number, since it uses as much as digits as its factorization.

21550540313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295212954.

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 21550540313 in words is "twenty-one billion, five hundred fifty million, five hundred forty thousand, three hundred thirteen".