55821864 has 32 divisors (see below), whose sum is σ = 159491520. Its totient is φ = 15949056.

The previous prime is 55821811. The next prime is 55821877. The reversal of 55821864 is 46812855.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165969 + ... + 166304.

It is an arithmetic number, because the mean of its divisors is an integer number (4984110).

Almost surely, 2^55821864 is an apocalyptic number.

It is an amenable number.

55821864 is an abundant number, since it is smaller than the sum of its proper divisors (103669656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55821864 is a wasteful number, since it uses less digits than its factorization.

55821864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332289 (or 332285 counting only the distinct ones).

The product of its digits is 76800, while the sum is 39.

The square root of 55821864 is about 7471.4030810819. The cubic root of 55821864 is about 382.1801367089.

Subtracting from 55821864 its reverse (46812855), we obtain a palindrome (9009009).

It can be divided in two parts, 558 and 21864, that added together give a palindrome (22422).

The spelling of 55821864 in words is "fifty-five million, eight hundred twenty-one thousand, eight hundred sixty-four".