1985712177409 has 9 divisors (see below), whose sum is σ = 2033027506209. Its totient is φ = 1939473640020.

The previous prime is 1985712177401. The next prime is 1985712177433. The reversal of 1985712177409 is 9047712175891.

The square root of 1985712177409 is 1409153.

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

It is not a de Polignac number, because 1985712177409 - 2³ = 1985712177401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1985712177401) 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, 60577194 + ... + 60609964.

Almost surely, 2^{1985712177409} is an apocalyptic number.

1985712177409 is the 1409153-rd square number.

1985712177409 is the 704577-th centered octagonal number.

It is an amenable number.

1985712177409 is a deficient number, since it is larger than the sum of its proper divisors (47315328800).

1985712177409 is an frugal number, since it uses more digits than its factorization.

1985712177409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65628 (or 32814 counting only the distinct ones).

The product of its (nonzero) digits is 8890560, while the sum is 61.

The spelling of 1985712177409 in words is "one trillion, nine hundred eighty-five billion, seven hundred twelve million, one hundred seventy-seven thousand, four hundred nine".