55554991 has 4 divisors (see below), whose sum is σ = 55570984. Its totient is φ = 55539000.

The previous prime is 55554953. The next prime is 55555001. The reversal of 55554991 is 19945555.

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 55554991 - 2⁹ = 55554479 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 (55554911) 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, 345 + ... + 10546.

It is an arithmetic number, because the mean of its divisors is an integer number (13892746).

Almost surely, 2^55554991 is an apocalyptic number.

55554991 is a deficient number, since it is larger than the sum of its proper divisors (15993).

55554991 is a wasteful number, since it uses less digits than its factorization.

55554991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15992.

The product of its digits is 202500, while the sum is 43.

The square root of 55554991 is about 7453.5220533651. The cubic root of 55554991 is about 381.5701216705.

The spelling of 55554991 in words is "fifty-five million, five hundred fifty-four thousand, nine hundred ninety-one".