7779831381 has 72 divisors (see below), whose sum is σ = 13923567840. Its totient is φ = 4325221152.

The previous prime is 7779831379. The next prime is 7779831403. The reversal of 7779831381 is 1831389777.

It is a happy number.

It is not a de Polignac number, because 7779831381 - 2¹ = 7779831379 is a prime.

It is a super-2 number, since 2×7779831381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7779831341) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 431730 + ... + 449388.

Almost surely, 2^7779831381 is an apocalyptic number.

It is an amenable number.

7779831381 is a deficient number, since it is larger than the sum of its proper divisors (6143736459).

7779831381 is a wasteful number, since it uses less digits than its factorization.

7779831381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17725 (or 17706 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 54.

The square root of 7779831381 is about 88203.3524362878. The cubic root of 7779831381 is about 1981.4816802038.

It can be divided in two parts, 7779 and 831381, that added together give a triangular number (839160 = T₁₂₉₅).

The spelling of 7779831381 in words is "seven billion, seven hundred seventy-nine million, eight hundred thirty-one thousand, three hundred eighty-one".