1375879721 has 4 divisors (see below), whose sum is σ = 1393296000. Its totient is φ = 1358463444.

The previous prime is 1375879651. The next prime is 1375879733. The reversal of 1375879721 is 1279785731.

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 a cyclic number.

It is not a de Polignac number, because 1375879721 - 2¹⁴ = 1375863337 is a prime.

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 1375879721.

It is not an unprimeable number, because it can be changed into a prime (1375879781) 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, 8708021 + ... + 8708178.

It is an arithmetic number, because the mean of its divisors is an integer number (348324000).

Almost surely, 2^1375879721 is an apocalyptic number.

It is an amenable number.

1375879721 is a deficient number, since it is larger than the sum of its proper divisors (17416279).

1375879721 is an equidigital number, since it uses as much as digits as its factorization.

1375879721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17416278.

The product of its digits is 740880, while the sum is 50.

The square root of 1375879721 is about 37092.8526942860. The cubic root of 1375879721 is about 1112.2271440588.

The spelling of 1375879721 in words is "one billion, three hundred seventy-five million, eight hundred seventy-nine thousand, seven hundred twenty-one".