55515440 has 20 divisors (see below), whose sum is σ = 129073584. Its totient is φ = 22206144.

The previous prime is 55515437. The next prime is 55515457. The reversal of 55515440 is 4451555.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 346892 + ... + 347051.

Almost surely, 2^55515440 is an apocalyptic number.

It is an amenable number.

55515440 is an abundant number, since it is smaller than the sum of its proper divisors (73558144).

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

55515440 is a wasteful number, since it uses less digits than its factorization.

55515440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693956 (or 693950 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 29.

The square root of 55515440 is about 7450.8684057632. The cubic root of 55515440 is about 381.4795503743.

Adding to 55515440 its reverse (4451555), we get a palindrome (59966995).

It can be divided in two parts, 55515 and 440, that added together give a palindrome (55955).

The spelling of 55515440 in words is "fifty-five million, five hundred fifteen thousand, four hundred forty".