55312640 has 72 divisors (see below), whose sum is σ = 134413440. Its totient is φ = 21805056.

The previous prime is 55312637. The next prime is 55312651. The reversal of 55312640 is 4621355.

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, 100847 + ... + 101393.

Almost surely, 2^55312640 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 55312640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67206720).

55312640 is an abundant number, since it is smaller than the sum of its proper divisors (79100800).

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

55312640 is an equidigital number, since it uses as much as digits as its factorization.

55312640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647 (or 633 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 55312640 is about 7437.2468024128. The cubic root of 55312640 is about 381.0144638502.

Adding to 55312640 its reverse (4621355), we get a palindrome (59933995).

The spelling of 55312640 in words is "fifty-five million, three hundred twelve thousand, six hundred forty".