55561813 has 8 divisors (see below), whose sum is σ = 58059648. Its totient is φ = 53070864.

The previous prime is 55561787. The next prime is 55561837. The reversal of 55561813 is 31816555.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55561813 - 2¹³ = 55553621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55561853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21720 + ... + 24142.

It is an arithmetic number, because the mean of its divisors is an integer number (7257456).

Almost surely, 2^55561813 is an apocalyptic number.

It is an amenable number.

55561813 is a deficient number, since it is larger than the sum of its proper divisors (2497835).

55561813 is a wasteful number, since it uses less digits than its factorization.

55561813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3443.

The product of its digits is 18000, while the sum is 34.

The square root of 55561813 is about 7453.9796753144. The cubic root of 55561813 is about 381.5857396182.

The spelling of 55561813 in words is "fifty-five million, five hundred sixty-one thousand, eight hundred thirteen".