778613381 has 24 divisors (see below), whose sum is σ = 977173344. Its totient is φ = 614930400.

The previous prime is 778613351. The next prime is 778613393. The reversal of 778613381 is 183316877.

It is not a de Polignac number, because 778613381 - 2¹⁸ = 778351237 is a prime.

It is a super-2 number, since 2×778613381² = 1212477594144502322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (778613321) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 668906 + ... + 670068.

It is an arithmetic number, because the mean of its divisors is an integer number (40715556).

Almost surely, 2^778613381 is an apocalyptic number.

It is an amenable number.

778613381 is a deficient number, since it is larger than the sum of its proper divisors (198559963).

778613381 is a wasteful number, since it uses less digits than its factorization.

778613381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2241 (or 2234 counting only the distinct ones).

The product of its digits is 169344, while the sum is 44.

The square root of 778613381 is about 27903.6445827422. The cubic root of 778613381 is about 919.9706122465.

The spelling of 778613381 in words is "seven hundred seventy-eight million, six hundred thirteen thousand, three hundred eighty-one".