781628 has 6 divisors (see below), whose sum is σ = 1367856. Its totient is φ = 390812.

The previous prime is 781619. The next prime is 781631. The reversal of 781628 is 826187.

It is a super-2 number, since 2×781628² = 1221884660768, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 781594 and 781603.

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 as a sum of consecutive naturals, namely, 97700 + ... + 97707.

It is an arithmetic number, because the mean of its divisors is an integer number (227976).

2⁷⁸¹⁶²⁸ is an apocalyptic number.

It is an amenable number.

781628 is a deficient number, since it is larger than the sum of its proper divisors (586228).

781628 is a wasteful number, since it uses less digits than its factorization.

781628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195411 (or 195409 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 781628 is about 884.0972797153. The cubic root of 781628 is about 92.1156390860.

The spelling of 781628 in words is "seven hundred eighty-one thousand, six hundred twenty-eight".