55631440 has 80 divisors (see below), whose sum is σ = 133866432. Its totient is φ = 21491712.

The previous prime is 55631431. The next prime is 55631441. The reversal of 55631440 is 4413655.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 55631399 and 55631408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55631441) 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, 519867 + ... + 519973.

Almost surely, 2^55631440 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 55631440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66933216).

55631440 is an abundant number, since it is smaller than the sum of its proper divisors (78234992).

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

55631440 is a wasteful number, since it uses less digits than its factorization.

55631440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 55631440 is about 7458.6486711736. The cubic root of 55631440 is about 381.7450671518.

The spelling of 55631440 in words is "fifty-five million, six hundred thirty-one thousand, four hundred forty".