1601665557 has 16 divisors (see below), whose sum is σ = 2262307392. Its totient is φ = 1004463360.

The previous prime is 1601665537. The next prime is 1601665573. The reversal of 1601665557 is 7555661061.

It is not a de Polignac number, because 1601665557 - 2¹⁸ = 1601403413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1601665537) 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, 113007 + ... + 126387.

It is an arithmetic number, because the mean of its divisors is an integer number (141394212).

Almost surely, 2^1601665557 is an apocalyptic number.

1601665557 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1601665557 is a deficient number, since it is larger than the sum of its proper divisors (660641835).

1601665557 is a wasteful number, since it uses less digits than its factorization.

1601665557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15748.

The product of its (nonzero) digits is 189000, while the sum is 42.

The square root of 1601665557 is about 40020.8140471930. The cubic root of 1601665557 is about 1170.0127977269.

The spelling of 1601665557 in words is "one billion, six hundred one million, six hundred sixty-five thousand, five hundred fifty-seven".