66021215507 has 4 divisors (see below), whose sum is σ = 71099770560. Its totient is φ = 60942660456.

The previous prime is 66021215497. The next prime is 66021215563. The reversal of 66021215507 is 70551212066.

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 66021215507 - 2³⁰ = 64947473683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66021215597) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2539277507 + ... + 2539277532.

It is an arithmetic number, because the mean of its divisors is an integer number (17774942640).

Almost surely, 2^66021215507 is an apocalyptic number.

66021215507 is a deficient number, since it is larger than the sum of its proper divisors (5078555053).

66021215507 is a wasteful number, since it uses less digits than its factorization.

66021215507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5078555052.

The product of its (nonzero) digits is 25200, while the sum is 35.

The spelling of 66021215507 in words is "sixty-six billion, twenty-one million, two hundred fifteen thousand, five hundred seven".