1605642243 has 4 divisors (see below), whose sum is σ = 2140856328. Its totient is φ = 1070428160.

The previous prime is 1605642223. The next prime is 1605642251. The reversal of 1605642243 is 3422465061.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1605642243 - 2⁵ = 1605642211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1605642223) 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, 267607038 + ... + 267607043.

It is an arithmetic number, because the mean of its divisors is an integer number (535214082).

Almost surely, 2^1605642243 is an apocalyptic number.

1605642243 is a deficient number, since it is larger than the sum of its proper divisors (535214085).

1605642243 is an equidigital number, since it uses as much as digits as its factorization.

1605642243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535214084.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 1605642243 is about 40070.4659693396. The cubic root of 1605642243 is about 1170.9803172550.

The spelling of 1605642243 in words is "one billion, six hundred five million, six hundred forty-two thousand, two hundred forty-three".