1661255623259 has 2 divisors, whose sum is σ = 1661255623260. Its totient is φ = 1661255623258.

The previous prime is 1661255623249. The next prime is 1661255623267. The reversal of 1661255623259 is 9523265521661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661255623259 - 2¹⁶ = 1661255557723 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1661255623259.

It is not a weakly prime, because it can be changed into another prime (1661255623249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830627811629 + 830627811630.

It is an arithmetic number, because the mean of its divisors is an integer number (830627811630).

Almost surely, 2^{1661255623259} is an apocalyptic number.

1661255623259 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661255623259 is an equidigital number, since it uses as much as digits as its factorization.

1661255623259 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832000, while the sum is 53.

The spelling of 1661255623259 in words is "one trillion, six hundred sixty-one billion, two hundred fifty-five million, six hundred twenty-three thousand, two hundred fifty-nine".