1561661652 has 12 divisors (see below), whose sum is σ = 3643877216. Its totient is φ = 520553880.

The previous prime is 1561661609. The next prime is 1561661663. The reversal of 1561661652 is 2561661651.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 1561661652.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65069224 + ... + 65069247.

Almost surely, 2^1561661652 is an apocalyptic number.

1561661652 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1561661652 is an abundant number, since it is smaller than the sum of its proper divisors (2082215564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1561661652 is a wasteful number, since it uses less digits than its factorization.

1561661652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130138478 (or 130138476 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The square root of 1561661652 is about 39517.8649726930. The cubic root of 1561661652 is about 1160.1896370503.

Subtracting 1561661652 from its reverse (2561661651), we obtain a palindrome (999999999).

The spelling of 1561661652 in words is "one billion, five hundred sixty-one million, six hundred sixty-one thousand, six hundred fifty-two".