781616 has 20 divisors (see below), whose sum is σ = 1652424. Its totient is φ = 355200.

The previous prime is 781607. The next prime is 781619. The reversal of 781616 is 616187.

It is a super-2 number, since 2×781616² = 1221847142912, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (781619) by changing a digit.

781616 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 2045 + ... + 2396.

2⁷⁸¹⁶¹⁶ is an apocalyptic number.

It is an amenable number.

781616 is an abundant number, since it is smaller than the sum of its proper divisors (870808).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

781616 is a wasteful number, since it uses less digits than its factorization.

781616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4460 (or 4454 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 781616 is about 884.0904931058. The cubic root of 781616 is about 92.1151676796.

The spelling of 781616 in words is "seven hundred eighty-one thousand, six hundred sixteen".