55557661 has 2 divisors, whose sum is σ = 55557662. Its totient is φ = 55557660.

The previous prime is 55557643. The next prime is 55557679. The reversal of 55557661 is 16675555.

It is a balanced prime because it is at equal distance from previous prime (55557643) and next prime (55557679).

It can be written as a sum of positive squares in only one way, i.e., 34222500 + 21335161 = 5850^2 + 4619^2 .

It is a cyclic number.

It is not a de Polignac number, because 55557661 - 2²³ = 47169053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55557631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27778830 + 27778831.

It is an arithmetic number, because the mean of its divisors is an integer number (27778831).

Almost surely, 2^55557661 is an apocalyptic number.

It is an amenable number.

55557661 is a deficient number, since it is larger than the sum of its proper divisors (1).

55557661 is an equidigital number, since it uses as much as digits as its factorization.

55557661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 157500, while the sum is 40.

The square root of 55557661 is about 7453.7011611682. The cubic root of 55557661 is about 381.5762343880.

The spelling of 55557661 in words is "fifty-five million, five hundred fifty-seven thousand, six hundred sixty-one".