66016621969 has 9 divisors (see below), whose sum is σ = 69679205193. Its totient is φ = 62537438052.

The previous prime is 66016621963. The next prime is 66016622027. The reversal of 66016621969 is 96912661066.

The square root of 66016621969 is 256937.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 66016621969 - 2³³ = 57426687377 is a prime.

It is a super-2 number, since 2×66016621969² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66016621963) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4875042 + ... + 4888564.

Almost surely, 2^66016621969 is an apocalyptic number.

66016621969 is the 256937-th square number.

66016621969 is the 128469-th centered octagonal number.

It is an amenable number.

66016621969 is a deficient number, since it is larger than the sum of its proper divisors (3662583224).

66016621969 is an frugal number, since it uses more digits than its factorization.

66016621969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27084 (or 13542 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 52.

The spelling of 66016621969 in words is "sixty-six billion, sixteen million, six hundred twenty-one thousand, nine hundred sixty-nine".