66500021555 has 48 divisors (see below), whose sum is σ = 92435902272. Its totient is φ = 45801888000.

The previous prime is 66500021543. The next prime is 66500021573. The reversal of 66500021555 is 55512000566.

It is not a de Polignac number, because 66500021555 - 2¹⁴ = 66500005171 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1381757 + ... + 1429073.

It is an arithmetic number, because the mean of its divisors is an integer number (1925747964).

Almost surely, 2^66500021555 is an apocalyptic number.

66500021555 is a deficient number, since it is larger than the sum of its proper divisors (25935880717).

66500021555 is a wasteful number, since it uses less digits than its factorization.

66500021555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47468 (or 47457 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 35.

The spelling of 66500021555 in words is "sixty-six billion, five hundred million, twenty-one thousand, five hundred fifty-five".