55021440 has 64 divisors (see below), whose sum is σ = 175386960. Its totient is φ = 14671872.

The previous prime is 55021423. The next prime is 55021471. The reversal of 55021440 is 4412055.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

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, 12409 + ... + 16248.

Almost surely, 2^55021440 is an apocalyptic number.

It is an amenable number.

55021440 is an abundant number, since it is smaller than the sum of its proper divisors (120365520).

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

55021440 is a wasteful number, since it uses less digits than its factorization.

55021440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28679 (or 28667 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 55021440 is about 7417.6438307592. The cubic root of 55021440 is about 380.3446549903.

Adding to 55021440 its reverse (4412055), we get a palindrome (59433495).

The spelling of 55021440 in words is "fifty-five million, twenty-one thousand, four hundred forty".