1605217123 has 2 divisors, whose sum is σ = 1605217124. Its totient is φ = 1605217122.

The previous prime is 1605217087. The next prime is 1605217153. The reversal of 1605217123 is 3217125061.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (3217125061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1605217123 - 2¹⁷ = 1605086051 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1605217091 and 1605217100.

It is not a weakly prime, because it can be changed into another prime (1605217153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802608561 + 802608562.

It is an arithmetic number, because the mean of its divisors is an integer number (802608562).

Almost surely, 2^1605217123 is an apocalyptic number.

1605217123 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605217123 is an equidigital number, since it uses as much as digits as its factorization.

1605217123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 1605217123 is about 40065.1609631111. The cubic root of 1605217123 is about 1170.8769627468.

The spelling of 1605217123 in words is "one billion, six hundred five million, two hundred seventeen thousand, one hundred twenty-three".