55218007 has 4 divisors (see below), whose sum is σ = 59465560. Its totient is φ = 50970456.

The previous prime is 55217959. The next prime is 55218019. The reversal of 55218007 is 70081255.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 55218007 - 2¹⁹ = 54693719 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 (55218307) 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, 2123757 + ... + 2123782.

It is an arithmetic number, because the mean of its divisors is an integer number (14866390).

Almost surely, 2^55218007 is an apocalyptic number.

55218007 is a deficient number, since it is larger than the sum of its proper divisors (4247553).

55218007 is a wasteful number, since it uses less digits than its factorization.

55218007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4247552.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 55218007 is about 7430.8819799537. The cubic root of 55218007 is about 380.7970504701.

The spelling of 55218007 in words is "fifty-five million, two hundred eighteen thousand, seven".