5515553661 has 16 divisors (see below), whose sum is σ = 7796793024. Its totient is φ = 3456237824.

The previous prime is 5515553647. The next prime is 5515553669. The reversal of 5515553661 is 1663555155.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 5515553661 - 2¹⁷ = 5515422589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5515553669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30531 + ... + 109376.

It is an arithmetic number, because the mean of its divisors is an integer number (487299564).

Almost surely, 2^5515553661 is an apocalyptic number.

5515553661 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

5515553661 is a deficient number, since it is larger than the sum of its proper divisors (2281239363).

5515553661 is a wasteful number, since it uses less digits than its factorization.

5515553661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140700.

The product of its digits is 337500, while the sum is 42.

The square root of 5515553661 is about 74266.7736003120. The cubic root of 5515553661 is about 1766.8365362036.

The spelling of 5515553661 in words is "five billion, five hundred fifteen million, five hundred fifty-three thousand, six hundred sixty-one".