55779561 has 12 divisors (see below), whose sum is σ = 80679300. Its totient is φ = 37136160.

The previous prime is 55779541. The next prime is 55779599. The reversal of 55779561 is 16597755.

It is a happy number.

55779561 is a `hidden beast` number, since 557 + 7 + 95 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 31573161 + 24206400 = 5619^2 + 4920^2 .

It is not a de Polignac number, because 55779561 - 2⁹ = 55779049 is a prime.

It is a super-2 number, since 2×55779561² = 6222718850705442, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55779511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3615 + ... + 11163.

It is an arithmetic number, because the mean of its divisors is an integer number (6723275).

Almost surely, 2^55779561 is an apocalyptic number.

It is an amenable number.

55779561 is a deficient number, since it is larger than the sum of its proper divisors (24899739).

55779561 is a wasteful number, since it uses less digits than its factorization.

55779561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8376 (or 8373 counting only the distinct ones).

The product of its digits is 330750, while the sum is 45.

The square root of 55779561 is about 7468.5715501694. The cubic root of 55779561 is about 382.0835708900.

The spelling of 55779561 in words is "fifty-five million, seven hundred seventy-nine thousand, five hundred sixty-one".