55521661 has 8 divisors (see below), whose sum is σ = 60105080. Its totient is φ = 50982912.

The previous prime is 55521659. The next prime is 55521673. The reversal of 55521661 is 16612555.

It can be written as a sum of positive squares in 4 ways, for example, as 6661561 + 48860100 = 2581^2 + 6990^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55521661 - 2¹ = 55521659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55521601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8556 + ... + 13573.

It is an arithmetic number, because the mean of its divisors is an integer number (7513135).

Almost surely, 2^55521661 is an apocalyptic number.

It is an amenable number.

55521661 is a deficient number, since it is larger than the sum of its proper divisors (4583419).

55521661 is a wasteful number, since it uses less digits than its factorization.

55521661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22335.

The product of its digits is 9000, while the sum is 31.

The square root of 55521661 is about 7451.2858621851. The cubic root of 55521661 is about 381.4937992370.

The spelling of 55521661 in words is "fifty-five million, five hundred twenty-one thousand, six hundred sixty-one".