1561521005 has 32 divisors (see below), whose sum is σ = 2085723648. Its totient is φ = 1112716800.

The previous prime is 1561520981. The next prime is 1561521047. The reversal of 1561521005 is 5001251651.

It is not a de Polignac number, because 1561521005 - 2²⁰ = 1560472429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1049372 + ... + 1050858.

It is an arithmetic number, because the mean of its divisors is an integer number (65178864).

Almost surely, 2^1561521005 is an apocalyptic number.

It is an amenable number.

1561521005 is a deficient number, since it is larger than the sum of its proper divisors (524202643).

1561521005 is a wasteful number, since it uses less digits than its factorization.

1561521005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1877.

The product of its (nonzero) digits is 1500, while the sum is 26.

The square root of 1561521005 is about 39516.0853956968. The cubic root of 1561521005 is about 1160.1548061827.

Adding to 1561521005 its reverse (5001251651), we get a palindrome (6562772656).

The spelling of 1561521005 in words is "one billion, five hundred sixty-one million, five hundred twenty-one thousand, five".