55991919 has 8 divisors (see below), whose sum is σ = 74852352. Its totient is φ = 37229720.

The previous prime is 55991909. The next prime is 55991939. The reversal of 55991919 is 91919955.

It is a happy number.

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 55991919 - 2⁷ = 55991791 is a prime.

It is a super-2 number, since 2×55991919² = 6270189986605122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55991909) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 23217 + ... + 25514.

It is an arithmetic number, because the mean of its divisors is an integer number (9356544).

Almost surely, 2^55991919 is an apocalyptic number.

55991919 is a deficient number, since it is larger than the sum of its proper divisors (18860433).

55991919 is a wasteful number, since it uses less digits than its factorization.

55991919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49117.

The product of its digits is 164025, while the sum is 48.

The square root of 55991919 is about 7482.7748195439. The cubic root of 55991919 is about 382.5678328158.

Subtracting 55991919 from its reverse (91919955), we obtain a square (35928036 = 5994²).

It can be divided in two parts, 55 and 991919, that multiplied together give a palindrome (54555545).

The spelling of 55991919 in words is "fifty-five million, nine hundred ninety-one thousand, nine hundred nineteen".