55261440 has 360 divisors, whose sum is σ = 218139768. Its totient is φ = 13271040.

The previous prime is 55261439. The next prime is 55261447. The reversal of 55261440 is 4416255.

55261440 is a `hidden beast` number, since 5 + 5 + 2 + 614 + 40 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1327104 + 53934336 = 1152^2 + 7344^2 .

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (55261447) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1347820 + ... + 1347860.

Almost surely, 2^55261440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55261440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109069884).

55261440 is an abundant number, since it is smaller than the sum of its proper divisors (162878328).

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

55261440 is a wasteful number, since it uses less digits than its factorization.

55261440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 55261440 is about 7433.8038715048. The cubic root of 55261440 is about 380.8968658786.

Adding to 55261440 its reverse (4416255), we get a palindrome (59677695).

The spelling of 55261440 in words is "fifty-five million, two hundred sixty-one thousand, four hundred forty".