1368813981 has 4 divisors (see below), whose sum is σ = 1825085312. Its totient is φ = 912542652.

The previous prime is 1368813967. The next prime is 1368813989. The reversal of 1368813981 is 1893188631.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1368813981 - 2¹⁵ = 1368781213 is a prime.

It is a super-2 number, since 2×1368813981² = 3747303429162136722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1368813981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1368813989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228135661 + ... + 228135666.

It is an arithmetic number, because the mean of its divisors is an integer number (456271328).

Almost surely, 2^1368813981 is an apocalyptic number.

It is an amenable number.

1368813981 is a deficient number, since it is larger than the sum of its proper divisors (456271331).

1368813981 is an equidigital number, since it uses as much as digits as its factorization.

1368813981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456271330.

The product of its digits is 248832, while the sum is 48.

The square root of 1368813981 is about 36997.4861443315. The cubic root of 1368813981 is about 1110.3199524056.

The spelling of 1368813981 in words is "one billion, three hundred sixty-eight million, eight hundred thirteen thousand, nine hundred eighty-one".