131778738 has 120 divisors (see below), whose sum is σ = 370203372. Its totient is φ = 34727616.

The previous prime is 131778733. The next prime is 131778761. The reversal of 131778738 is 837877131.

It can be written as a sum of positive squares in 2 ways, for example, as 130028409 + 1750329 = 11403^2 + 1323^2 .

It is a junction number, because it is equal to n+sod(n) for n = 131778693 and 131778702.

It is not an unprimeable number, because it can be changed into a prime (131778733) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 102556 + ... + 103832.

Almost surely, 2^131778738 is an apocalyptic number.

131778738 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 131778738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185101686).

131778738 is an abundant number, since it is smaller than the sum of its proper divisors (238424634).

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

131778738 is a wasteful number, since it uses less digits than its factorization.

131778738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1318 (or 1302 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The square root of 131778738 is about 11479.4920619338. The cubic root of 131778738 is about 508.8796861442.

The spelling of 131778738 in words is "one hundred thirty-one million, seven hundred seventy-eight thousand, seven hundred thirty-eight".