1390266665 has 8 divisors (see below), whose sum is σ = 1672401480. Its totient is φ = 1109492352.

The previous prime is 1390266643. The next prime is 1390266667. The reversal of 1390266665 is 5666620931.

It can be written as a sum of positive squares in 4 ways, for example, as 119486761 + 1270779904 = 10931^2 + 35648^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1390266665 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1390266667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 337874 + ... + 341963.

It is an arithmetic number, because the mean of its divisors is an integer number (209050185).

Almost surely, 2^1390266665 is an apocalyptic number.

It is an amenable number.

1390266665 is a deficient number, since it is larger than the sum of its proper divisors (282134815).

1390266665 is an equidigital number, since it uses as much as digits as its factorization.

1390266665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680251.

The product of its (nonzero) digits is 349920, while the sum is 44.

The square root of 1390266665 is about 37286.2798492958. The cubic root of 1390266665 is about 1116.0903930349.

It can be divided in two parts, 1390266 and 665, that added together give a palindrome (1390931).

The spelling of 1390266665 in words is "one billion, three hundred ninety million, two hundred sixty-six thousand, six hundred sixty-five".