21115645355 has 16 divisors (see below), whose sum is σ = 28978145280. Its totient is φ = 14469526752.

The previous prime is 21115645337. The next prime is 21115645399. The reversal of 21115645355 is 55354651112.

It is a cyclic number.

It is not a de Polignac number, because 21115645355 - 2⁸ = 21115645099 is a prime.

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, 150815 + ... + 254904.

It is an arithmetic number, because the mean of its divisors is an integer number (1811134080).

Almost surely, 2^21115645355 is an apocalyptic number.

21115645355 is a deficient number, since it is larger than the sum of its proper divisors (7862499925).

21115645355 is a wasteful number, since it uses less digits than its factorization.

21115645355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407218.

The product of its digits is 90000, while the sum is 38.

The spelling of 21115645355 in words is "twenty-one billion, one hundred fifteen million, six hundred forty-five thousand, three hundred fifty-five".