1605215656901 has 2 divisors, whose sum is σ = 1605215656902. Its totient is φ = 1605215656900.

The previous prime is 1605215656873. The next prime is 1605215656907. The reversal of 1605215656901 is 1096565125061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 908990628100 + 696225028801 = 953410^2 + 834401^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1605215656901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1605215656907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802607828450 + 802607828451.

It is an arithmetic number, because the mean of its divisors is an integer number (802607828451).

Almost surely, 2^{1605215656901} is an apocalyptic number.

It is an amenable number.

1605215656901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605215656901 is an equidigital number, since it uses as much as digits as its factorization.

1605215656901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 486000, while the sum is 47.

The spelling of 1605215656901 in words is "one trillion, six hundred five billion, two hundred fifteen million, six hundred fifty-six thousand, nine hundred one".