1664541405 has 24 divisors (see below), whose sum is σ = 2888110680. Its totient is φ = 886861440.

The previous prime is 1664541397. The next prime is 1664541407. The reversal of 1664541405 is 5041454661.

1664541405 is a `hidden beast` number, since 1 + 6 + 645 + 4 + 1 + 4 + 0 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 227979801 + 1436561604 = 15099^2 + 37902^2 .

It is not a de Polignac number, because 1664541405 - 2³ = 1664541397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1664541405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664541407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27831 + ... + 64059.

It is an arithmetic number, because the mean of its divisors is an integer number (120337945).

Almost surely, 2^1664541405 is an apocalyptic number.

1664541405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664541405 is a deficient number, since it is larger than the sum of its proper divisors (1223569275).

1664541405 is a wasteful number, since it uses less digits than its factorization.

1664541405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37261 (or 37258 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 1664541405 is about 40798.7917100495. The cubic root of 1664541405 is about 1185.1269318713.

The spelling of 1664541405 in words is "one billion, six hundred sixty-four million, five hundred forty-one thousand, four hundred five".