1605537040221 has 10 divisors (see below), whose sum is σ = 2398394837982. Its totient is φ = 1070358026760.

The previous prime is 1605537040207. The next prime is 1605537040241. The reversal of 1605537040221 is 1220407355061.

1605537040221 is a `hidden beast` number, since 1 + 60 + 5 + 5 + 370 + 4 + 0 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1516873044996 + 88663995225 = 1231614^2 + 297765^2 .

It is not a de Polignac number, because 1605537040221 - 2⁶ = 1605537040157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605537040241) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9910722390 + ... + 9910722551.

Almost surely, 2^{1605537040221} is an apocalyptic number.

It is an amenable number.

1605537040221 is a deficient number, since it is larger than the sum of its proper divisors (792857797761).

1605537040221 is an equidigital number, since it uses as much as digits as its factorization.

1605537040221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19821444953 (or 19821444944 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 1605537040221 in words is "one trillion, six hundred five billion, five hundred thirty-seven million, forty thousand, two hundred twenty-one".