1655661557 has 4 divisors (see below), whose sum is σ = 1806176256. Its totient is φ = 1505146860.

The previous prime is 1655661529. The next prime is 1655661587. The reversal of 1655661557 is 7551665561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7551665561 = 11 ⋅686515051.

It is a cyclic number.

It is not a de Polignac number, because 1655661557 - 2²² = 1651467253 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 (1655661517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75257333 + ... + 75257354.

It is an arithmetic number, because the mean of its divisors is an integer number (451544064).

Almost surely, 2^1655661557 is an apocalyptic number.

It is an amenable number.

1655661557 is a deficient number, since it is larger than the sum of its proper divisors (150514699).

1655661557 is a wasteful number, since it uses less digits than its factorization.

1655661557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150514698.

The product of its digits is 945000, while the sum is 47.

The square root of 1655661557 is about 40689.8212947661. The cubic root of 1655661557 is about 1183.0157364869.

The spelling of 1655661557 in words is "one billion, six hundred fifty-five million, six hundred sixty-one thousand, five hundred fifty-seven".