781242638 has 8 divisors (see below), whose sum is σ = 1278397080. Its totient is φ = 355110280.

The previous prime is 781242557. The next prime is 781242647. The reversal of 781242638 is 836242187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×781242638² = 1220680118858398088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 781242595 and 781242604.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 17755493 + ... + 17755536.

It is an arithmetic number, because the mean of its divisors is an integer number (159799635).

Almost surely, 2^781242638 is an apocalyptic number.

781242638 is a deficient number, since it is larger than the sum of its proper divisors (497154442).

781242638 is a wasteful number, since it uses less digits than its factorization.

781242638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35511042.

The product of its digits is 129024, while the sum is 41.

The square root of 781242638 is about 27950.7180229775. The cubic root of 781242638 is about 921.0049816548.

The spelling of 781242638 in words is "seven hundred eighty-one million, two hundred forty-two thousand, six hundred thirty-eight".