1545315661 has 4 divisors (see below), whose sum is σ = 1546125372. Its totient is φ = 1544505952.

The previous prime is 1545315659. The next prime is 1545315703. The reversal of 1545315661 is 1665135451.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1360872100 + 184443561 = 36890^2 + 13581^2 .

It is a cyclic number.

It is not a de Polignac number, because 1545315661 - 2¹ = 1545315659 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1545315661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1545315601) 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, 401986 + ... + 405811.

It is an arithmetic number, because the mean of its divisors is an integer number (386531343).

Almost surely, 2^1545315661 is an apocalyptic number.

It is an amenable number.

1545315661 is a deficient number, since it is larger than the sum of its proper divisors (809711).

1545315661 is an equidigital number, since it uses as much as digits as its factorization.

1545315661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 809710.

The product of its digits is 54000, while the sum is 37.

The square root of 1545315661 is about 39310.5031893513. The cubic root of 1545315661 is about 1156.1275100006.

It can be divided in two parts, 1545 and 315661, that added together give a triangular number (317206 = T₇₉₆).

The spelling of 1545315661 in words is "one billion, five hundred forty-five million, three hundred fifteen thousand, six hundred sixty-one".