21255361315 has 4 divisors (see below), whose sum is σ = 25506433584. Its totient is φ = 17004289048.

The previous prime is 21255361301. The next prime is 21255361363. The reversal of 21255361315 is 51316355212.

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

It is a cyclic number.

It is not a de Polignac number, because 21255361315 - 2¹⁵ = 21255328547 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2125536127 + ... + 2125536136.

It is an arithmetic number, because the mean of its divisors is an integer number (6376608396).

Almost surely, 2^21255361315 is an apocalyptic number.

21255361315 is a deficient number, since it is larger than the sum of its proper divisors (4251072269).

21255361315 is an equidigital number, since it uses as much as digits as its factorization.

21255361315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4251072268.

The product of its digits is 27000, while the sum is 34.

The spelling of 21255361315 in words is "twenty-one billion, two hundred fifty-five million, three hundred sixty-one thousand, three hundred fifteen".