21155565713 has 8 divisors (see below), whose sum is σ = 22270605600. Its totient is φ = 20040684768.

The previous prime is 21155565679. The next prime is 21155565721. The reversal of 21155565713 is 31756555112.

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 21155565713 - 2⁶ = 21155565649 is a prime.

It is a super-2 number, since 2×21155565713² (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 (21155565763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314570 + ... + 375852.

It is an arithmetic number, because the mean of its divisors is an integer number (2783825700).

Almost surely, 2^21155565713 is an apocalyptic number.

It is an amenable number.

21155565713 is a deficient number, since it is larger than the sum of its proper divisors (1115039887).

21155565713 is a wasteful number, since it uses less digits than its factorization.

21155565713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79471.

The product of its digits is 157500, while the sum is 41.

The spelling of 21155565713 in words is "twenty-one billion, one hundred fifty-five million, five hundred sixty-five thousand, seven hundred thirteen".