531681778 has 4 divisors (see below), whose sum is σ = 797522670. Its totient is φ = 265840888.

The previous prime is 531681767. The next prime is 531681781. The reversal of 531681778 is 877186135.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 413024329 + 118657449 = 20323^2 + 10893^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132920443 + ... + 132920446.

Almost surely, 2^531681778 is an apocalyptic number.

531681778 is a deficient number, since it is larger than the sum of its proper divisors (265840892).

531681778 is a wasteful number, since it uses less digits than its factorization.

531681778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265840891.

The product of its digits is 282240, while the sum is 46.

The square root of 531681778 is about 23058.2258207348. The cubic root of 531681778 is about 810.1223094276.

It can be divided in two parts, 53168 and 1778, that added together give a triangular number (54946 = T₃₃₁).

The spelling of 531681778 in words is "five hundred thirty-one million, six hundred eighty-one thousand, seven hundred seventy-eight".