1516561601 has 4 divisors (see below), whose sum is σ = 1516811604. Its totient is φ = 1516311600.

The previous prime is 1516561577. The next prime is 1516561621. The reversal of 1516561601 is 1061656151.

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 402604225 + 1113957376 = 20065^2 + 33376^2 .

It is a cyclic number.

It is not a de Polignac number, because 1516561601 - 2⁶ = 1516561537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1516561621) 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, 115670 + ... + 128111.

It is an arithmetic number, because the mean of its divisors is an integer number (379202901).

Almost surely, 2^1516561601 is an apocalyptic number.

It is an amenable number.

1516561601 is a deficient number, since it is larger than the sum of its proper divisors (250003).

1516561601 is an equidigital number, since it uses as much as digits as its factorization.

1516561601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250002.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1516561601 is about 38943.0558764974. The cubic root of 1516561601 is about 1148.9117874672.

The spelling of 1516561601 in words is "one billion, five hundred sixteen million, five hundred sixty-one thousand, six hundred one".