5661616521 has 32 divisors (see below), whose sum is σ = 8509685760. Its totient is φ = 3317097600.

The previous prime is 5661616483. The next prime is 5661616529. The reversal of 5661616521 is 1256161665.

It is not a de Polignac number, because 5661616521 - 2⁷ = 5661616393 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 5661616521.

It is not an unprimeable number, because it can be changed into a prime (5661616529) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1218120 + ... + 1222758.

It is an arithmetic number, because the mean of its divisors is an integer number (265927680).

Almost surely, 2^5661616521 is an apocalyptic number.

It is an amenable number.

5661616521 is a deficient number, since it is larger than the sum of its proper divisors (2848069239).

5661616521 is a wasteful number, since it uses less digits than its factorization.

5661616521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5877.

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

The square root of 5661616521 is about 75243.7141627126. The cubic root of 5661616521 is about 1782.2973032110.

It can be divided in two parts, 56616 and 16521, that added together give a palindrome (73137).

The spelling of 5661616521 in words is "five billion, six hundred sixty-one million, six hundred sixteen thousand, five hundred twenty-one".