781628881 has 8 divisors (see below), whose sum is σ = 853668864. Its totient is φ = 709752720.

The previous prime is 781628843. The next prime is 781628933. The reversal of 781628881 is 188826187.

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

It is a cyclic number.

It is not a de Polignac number, because 781628881 - 2¹⁵ = 781596113 is a prime.

It is a super-2 number, since 2×781628881² = 1221887415226624322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (781698881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30865 + ... + 50158.

It is an arithmetic number, because the mean of its divisors is an integer number (106708608).

Almost surely, 2^781628881 is an apocalyptic number.

It is an amenable number.

781628881 is a deficient number, since it is larger than the sum of its proper divisors (72039983).

781628881 is a wasteful number, since it uses less digits than its factorization.

781628881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81911.

The product of its digits is 344064, while the sum is 49.

The square root of 781628881 is about 27957.6265265848. The cubic root of 781628881 is about 921.1567369490.

The spelling of 781628881 in words is "seven hundred eighty-one million, six hundred twenty-eight thousand, eight hundred eighty-one".