1806505347969 has 81 divisors (see below), whose sum is σ = 3145124591427. Its totient is φ = 996241000608.

The previous prime is 1806505347961. The next prime is 1806505348003. The reversal of 1806505347969 is 9697435056081.

The square root of 1806505347969 is 1344063.

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

1806505347969 is a `hidden beast` number, since 1 + 8 + 0 + 6 + 5 + 0 + 534 + 7 + 96 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 947287584369 + 859217763600 = 973287^2 + 926940^2 .

It is not a de Polignac number, because 1806505347969 - 2³ = 1806505347961 is a prime.

It is a super-2 number, since 2×1806505347969² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (1806505347961) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 818533264 + ... + 818535470.

Almost surely, 2^{1806505347969} is an apocalyptic number.

1806505347969 is the 1344063-rd square number.

1806505347969 is the 672032-nd centered octagonal number.

It is an amenable number.

1806505347969 is a deficient number, since it is larger than the sum of its proper divisors (1338619243458).

1806505347969 is an frugal number, since it uses more digits than its factorization.

1806505347969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4492 (or 2246 counting only the distinct ones).

The product of its (nonzero) digits is 48988800, while the sum is 63.

The spelling of 1806505347969 in words is "one trillion, eight hundred six billion, five hundred five million, three hundred forty-seven thousand, nine hundred sixty-nine".