55721211 has 16 divisors (see below), whose sum is σ = 91440384. Its totient is φ = 29391264.

The previous prime is 55721207. The next prime is 55721219. The reversal of 55721211 is 11212755.

It is not a de Polignac number, because 55721211 - 2² = 55721207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (55721219) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101781 + ... + 102326.

It is an arithmetic number, because the mean of its divisors is an integer number (5715024).

Almost surely, 2^55721211 is an apocalyptic number.

55721211 is a deficient number, since it is larger than the sum of its proper divisors (35719173).

55721211 is a wasteful number, since it uses less digits than its factorization.

55721211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204130.

The product of its digits is 700, while the sum is 24.

The square root of 55721211 is about 7464.6641585540. The cubic root of 55721211 is about 381.9502941457.

Adding to 55721211 its reverse (11212755), we get a palindrome (66933966).

The spelling of 55721211 in words is "fifty-five million, seven hundred twenty-one thousand, two hundred eleven".