21505266750516 has 48 divisors (see below), whose sum is σ = 53125271169600. Its totient is φ = 6751881729792.

The previous prime is 21505266750491. The next prime is 21505266750523. The reversal of 21505266750516 is 61505766250512.

It is a congruent number.

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, 272565601 + ... + 272644488.

It is an arithmetic number, because the mean of its divisors is an integer number (1106776482700).

Almost surely, 2^{21505266750516} is an apocalyptic number.

It is an amenable number.

21505266750516 is an abundant number, since it is smaller than the sum of its proper divisors (31620004419084).

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

21505266750516 is a wasteful number, since it uses less digits than its factorization.

21505266750516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545210288 (or 545210286 counting only the distinct ones).

The product of its (nonzero) digits is 3780000, while the sum is 51.

The spelling of 21505266750516 in words is "twenty-one trillion, five hundred five billion, two hundred sixty-six million, seven hundred fifty thousand, five hundred sixteen".