669780196801 has 9 divisors (see below), whose sum is σ = 686549135209. Its totient is φ = 653411358400.

The previous prime is 669780196747. The next prime is 669780196843. The reversal of 669780196801 is 108691087966.

The square root of 669780196801 is 818401.

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

669780196801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1572043201 + 668208153600 = 39649^2 + 817440^2 .

It is not a de Polignac number, because 669780196801 - 2²¹ = 669778099649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 669780196801.

It is not an unprimeable number, because it can be changed into a prime (669780196861) 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, 33544461 + ... + 33564421.

Almost surely, 2^669780196801 is an apocalyptic number.

669780196801 is the 818401-st square number.

669780196801 is the 409201-st centered octagonal number.

It is an amenable number.

669780196801 is a deficient number, since it is larger than the sum of its proper divisors (16768938408).

669780196801 is an frugal number, since it uses more digits than its factorization.

669780196801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40004 (or 20002 counting only the distinct ones).

The product of its (nonzero) digits is 7838208, while the sum is 61.

The spelling of 669780196801 in words is "six hundred sixty-nine billion, seven hundred eighty million, one hundred ninety-six thousand, eight hundred one".