55561645 has 4 divisors (see below), whose sum is σ = 66673980. Its totient is φ = 44449312.

The previous prime is 55561631. The next prime is 55561663. The reversal of 55561645 is 54616555.

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 27237961 + 28323684 = 5219^2 + 5322^2 .

It is a cyclic number.

It is not a de Polignac number, because 55561645 - 2¹¹ = 55559597 is a prime.

It is a super-3 number, since 3×55561645³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5556160 + ... + 5556169.

It is an arithmetic number, because the mean of its divisors is an integer number (16668495).

Almost surely, 2^55561645 is an apocalyptic number.

It is an amenable number.

55561645 is a deficient number, since it is larger than the sum of its proper divisors (11112335).

55561645 is a wasteful number, since it uses less digits than its factorization.

55561645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11112334.

The product of its digits is 90000, while the sum is 37.

The square root of 55561645 is about 7453.9684061579. The cubic root of 55561645 is about 381.5853550227.

The spelling of 55561645 in words is "fifty-five million, five hundred sixty-one thousand, six hundred forty-five".