1366905978 has 24 divisors (see below), whose sum is σ = 3135843828. Its totient is φ = 428833152.

The previous prime is 1366905977. The next prime is 1366905997. The reversal of 1366905978 is 8795096631.

It can be written as a sum of positive squares in 2 ways, for example, as 1356964569 + 9941409 = 36837^2 + 3153^2 .

It is not an unprimeable number, because it can be changed into a prime (1366905977) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2233201 + ... + 2233812.

Almost surely, 2^1366905978 is an apocalyptic number.

1366905978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1366905978 is an abundant number, since it is smaller than the sum of its proper divisors (1768937850).

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

1366905978 is a wasteful number, since it uses less digits than its factorization.

1366905978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4467038 (or 4467035 counting only the distinct ones).

The product of its (nonzero) digits is 2449440, while the sum is 54.

The square root of 1366905978 is about 36971.6915761235. The cubic root of 1366905978 is about 1109.8038172885.

The spelling of 1366905978 in words is "one billion, three hundred sixty-six million, nine hundred five thousand, nine hundred seventy-eight".