55665390 has 128 divisors (see below), whose sum is σ = 154441728. Its totient is φ = 12718080.

The previous prime is 55665341. The next prime is 55665391. The reversal of 55665390 is 9356655.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55665391) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 573822 + ... + 573918.

It is an arithmetic number, because the mean of its divisors is an integer number (1206576).

Almost surely, 2^55665390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55665390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77220864).

55665390 is an abundant number, since it is smaller than the sum of its proper divisors (98776338).

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

55665390 is a wasteful number, since it uses less digits than its factorization.

55665390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202.

The product of its (nonzero) digits is 121500, while the sum is 39.

The square root of 55665390 is about 7460.9242054855. The cubic root of 55665390 is about 381.8227067594.

The spelling of 55665390 in words is "fifty-five million, six hundred sixty-five thousand, three hundred ninety".