55621665 has 48 divisors (see below), whose sum is σ = 105805440. Its totient is φ = 26807040.

The previous prime is 55621663. The next prime is 55621673. The reversal of 55621665 is 56612655.

It is a happy number.

It is not a de Polignac number, because 55621665 - 2¹ = 55621663 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (55621663) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 154756 + ... + 155114.

It is an arithmetic number, because the mean of its divisors is an integer number (2204280).

Almost surely, 2^55621665 is an apocalyptic number.

55621665 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

55621665 is a deficient number, since it is larger than the sum of its proper divisors (50183775).

55621665 is a wasteful number, since it uses less digits than its factorization.

55621665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694 (or 691 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The square root of 55621665 is about 7457.9933628289. The cubic root of 55621665 is about 381.7227070342.

It can be divided in two parts, 5562 and 1665, that added together give a palindrome (7227).

The spelling of 55621665 in words is "fifty-five million, six hundred twenty-one thousand, six hundred sixty-five".