1381688778 has 16 divisors (see below), whose sum is σ = 2908818720. Its totient is φ = 436322736.

The previous prime is 1381688723. The next prime is 1381688809. The reversal of 1381688778 is 8778861831.

It is a super-2 number, since 2×1381688778² = 3818127758502266568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6059925 + ... + 6060152.

It is an arithmetic number, because the mean of its divisors is an integer number (181801170).

Almost surely, 2^1381688778 is an apocalyptic number.

1381688778 is an abundant number, since it is smaller than the sum of its proper divisors (1527129942).

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

1381688778 is a wasteful number, since it uses less digits than its factorization.

1381688778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12120101.

The product of its digits is 3612672, while the sum is 57.

The square root of 1381688778 is about 37171.0744800308. The cubic root of 1381688778 is about 1113.7902456230.

The spelling of 1381688778 in words is "one billion, three hundred eighty-one million, six hundred eighty-eight thousand, seven hundred seventy-eight".