616863781 has 4 divisors (see below), whose sum is σ = 626976364. Its totient is φ = 606751200.

The previous prime is 616863773. The next prime is 616863817. The reversal of 616863781 is 187368616.

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

It can be written as a sum of positive squares in 2 ways, for example, as 361950625 + 254913156 = 19025^2 + 15966^2 .

It is a cyclic number.

It is not a de Polignac number, because 616863781 - 2³ = 616863773 is a prime.

It is a super-2 number, since 2×616863781² = 761041848619231922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (616863281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5056200 + ... + 5056321.

It is an arithmetic number, because the mean of its divisors is an integer number (156744091).

Almost surely, 2^616863781 is an apocalyptic number.

616863781 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

616863781 is the 14340-th hex number.

It is an amenable number.

616863781 is a deficient number, since it is larger than the sum of its proper divisors (10112583).

616863781 is a wasteful number, since it uses less digits than its factorization.

616863781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10112582.

The product of its digits is 290304, while the sum is 46.

The square root of 616863781 is about 24836.7425601668. The cubic root of 616863781 is about 851.2616930679.

The spelling of 616863781 in words is "six hundred sixteen million, eight hundred sixty-three thousand, seven hundred eighty-one".