21165650056215 has 32 divisors (see below), whose sum is σ = 43003225512960. Its totient is φ = 9675725739552.

The previous prime is 21165650056211. The next prime is 21165650056253. The reversal of 21165650056215 is 51265005656112.

It is a happy number.

21165650056215 is a `hidden beast` number, since 2 + 1 + 16 + 5 + 6 + 5 + 0 + 0 + 5 + 621 + 5 = 666.

It is not a de Polignac number, because 21165650056215 - 2² = 21165650056211 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165650056211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11198755699 + ... + 11198757588.

It is an arithmetic number, because the mean of its divisors is an integer number (1343850797280).

Almost surely, 2^{21165650056215} is an apocalyptic number.

21165650056215 is an abundant number, since it is smaller than the sum of its proper divisors (21837575456745).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21165650056215 is a wasteful number, since it uses less digits than its factorization.

21165650056215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22397513308 (or 22397513302 counting only the distinct ones).

The product of its (nonzero) digits is 540000, while the sum is 45.

The spelling of 21165650056215 in words is "twenty-one trillion, one hundred sixty-five billion, six hundred fifty million, fifty-six thousand, two hundred fifteen".