206986781764 has 27 divisors (see below), whose sum is σ = 421378915293. Its totient is φ = 88705891008.

The previous prime is 206986781719. The next prime is 206986781767. The reversal of 206986781764 is 467187689602.

The square root of 206986781764 is 454958.

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

206986781764 is digitally balanced in base 3, 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 only one way, i.e., 170049016900 + 36937764864 = 412370^2 + 192192^2 .

It is a junction number, because it is equal to n+sod(n) for n = 206986781696 and 206986781705.

It is not an unprimeable number, because it can be changed into a prime (206986781767) 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, 6353164 + ... + 6385660.

Almost surely, 2^206986781764 is an apocalyptic number.

206986781764 is the 454958-th square number.

It is an amenable number.

206986781764 is an abundant number, since it is smaller than the sum of its proper divisors (214392133529).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

206986781764 is an frugal number, since it uses more digits than its factorization.

206986781764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65012 (or 32506 counting only the distinct ones).

The product of its (nonzero) digits is 48771072, while the sum is 64.

Multiplying 206986781764 by its sum of digits (64), we get a square (13247154032896 = 3639664²).

The spelling of 206986781764 in words is "two hundred six billion, nine hundred eighty-six million, seven hundred eighty-one thousand, seven hundred sixty-four".