55215511 has 12 divisors (see below), whose sum is σ = 60477840. Its totient is φ = 50381760.

The previous prime is 55215509. The next prime is 55215533. The reversal of 55215511 is 11551255.

55215511 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 55215511 - 2¹ = 55215509 is a prime.

It is a super-2 number, since 2×55215511² = 6097505309982242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55215551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13206 + ... + 16876.

It is an arithmetic number, because the mean of its divisors is an integer number (5039820).

Almost surely, 2^55215511 is an apocalyptic number.

55215511 is a deficient number, since it is larger than the sum of its proper divisors (5262329).

55215511 is a wasteful number, since it uses less digits than its factorization.

55215511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3786 (or 3773 counting only the distinct ones).

The product of its digits is 1250, while the sum is 25.

The square root of 55215511 is about 7430.7140302935. The cubic root of 55215511 is about 380.7913127057.

Adding to 55215511 its reverse (11551255), we get a palindrome (66766766).

The spelling of 55215511 in words is "fifty-five million, two hundred fifteen thousand, five hundred eleven".