1378781956 has 6 divisors (see below), whose sum is σ = 2412868430. Its totient is φ = 689390976.

The previous prime is 1378781951. The next prime is 1378781981. The reversal of 1378781956 is 6591878731.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 781761600 + 597020356 = 27960^2 + 24434^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1378781897 and 1378781906.

It is not an unprimeable number, because it can be changed into a prime (1378781951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172347741 + ... + 172347748.

Almost surely, 2^1378781956 is an apocalyptic number.

It is an amenable number.

1378781956 is a deficient number, since it is larger than the sum of its proper divisors (1034086474).

1378781956 is a wasteful number, since it uses less digits than its factorization.

1378781956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344695493 (or 344695491 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 55.

The square root of 1378781956 is about 37131.9533017050. The cubic root of 1378781956 is about 1113.0086265079.

The spelling of 1378781956 in words is "one billion, three hundred seventy-eight million, seven hundred eighty-one thousand, nine hundred fifty-six".