1379975981 has 4 divisors (see below), whose sum is σ = 1381896000. Its totient is φ = 1378055964.

The previous prime is 1379975963. The next prime is 1379976007. The reversal of 1379975981 is 1895799731.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1895799731 = 7 ⋅270828533.

It is a cyclic number.

It is not a de Polignac number, because 1379975981 - 2⁶ = 1379975917 is a prime.

It is a super-2 number, since 2×1379975981² = 3808667416273824722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1379975981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1379975911) 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, 958931 + ... + 960368.

It is an arithmetic number, because the mean of its divisors is an integer number (345474000).

Almost surely, 2^1379975981 is an apocalyptic number.

It is an amenable number.

1379975981 is a deficient number, since it is larger than the sum of its proper divisors (1920019).

1379975981 is an equidigital number, since it uses as much as digits as its factorization.

1379975981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920018.

The product of its digits is 4286520, while the sum is 59.

The square root of 1379975981 is about 37148.0279557341. The cubic root of 1379975981 is about 1113.3298222506.

The spelling of 1379975981 in words is "one billion, three hundred seventy-nine million, nine hundred seventy-five thousand, nine hundred eighty-one".