1366901991 has 48 divisors (see below), whose sum is σ = 2479713600. Its totient is φ = 720982080.

The previous prime is 1366901957. The next prime is 1366902001. The reversal of 1366901991 is 1991096631.

It is not a de Polignac number, because 1366901991 - 2¹⁵ = 1366869223 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1366901191) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23101 + ... + 57161.

It is an arithmetic number, because the mean of its divisors is an integer number (51660700).

Almost surely, 2^1366901991 is an apocalyptic number.

1366901991 is a deficient number, since it is larger than the sum of its proper divisors (1112811609).

1366901991 is a wasteful number, since it uses less digits than its factorization.

1366901991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34101 (or 34084 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 45.

The square root of 1366901991 is about 36971.6376564523. The cubic root of 1366901991 is about 1109.8027382599.

The spelling of 1366901991 in words is "one billion, three hundred sixty-six million, nine hundred one thousand, nine hundred ninety-one".