781820042 has 16 divisors (see below), whose sum is σ = 1194626664. Its totient is φ = 383640000.

The previous prime is 781820041. The next prime is 781820047. The reversal of 781820042 is 240028187.

It can be written as a sum of positive squares in 4 ways, for example, as 520706761 + 261113281 = 22819^2 + 16159^2 .

It is a super-2 number, since 2×781820042² = 1222485156145763528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 781819990 and 781820008.

It is not an unprimeable number, because it can be changed into a prime (781820041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49292 + ... + 63192.

Almost surely, 2^781820042 is an apocalyptic number.

781820042 is a deficient number, since it is larger than the sum of its proper divisors (412806622).

781820042 is a wasteful number, since it uses less digits than its factorization.

781820042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14425.

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 781820042 is about 27961.0450806117. The cubic root of 781820042 is about 921.2318258196.

The spelling of 781820042 in words is "seven hundred eighty-one million, eight hundred twenty thousand, forty-two".