55661553 has 16 divisors (see below), whose sum is σ = 87312960. Its totient is φ = 34924608.

The previous prime is 55661549. The next prime is 55661561. The reversal of 55661553 is 35516655.

It is not a de Polignac number, because 55661553 - 2² = 55661549 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (55661533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60175 + ... + 61092.

It is an arithmetic number, because the mean of its divisors is an integer number (5457060).

Almost surely, 2^55661553 is an apocalyptic number.

It is an amenable number.

55661553 is a deficient number, since it is larger than the sum of its proper divisors (31651407).

55661553 is a wasteful number, since it uses less digits than its factorization.

55661553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121293 (or 121287 counting only the distinct ones).

The product of its digits is 67500, while the sum is 36.

The square root of 55661553 is about 7460.6670613290. The cubic root of 55661553 is about 381.8139335798.

The spelling of 55661553 in words is "fifty-five million, six hundred sixty-one thousand, five hundred fifty-three".