1661197617 has 6 divisors (see below), whose sum is σ = 2399507682. Its totient is φ = 1107465072.

The previous prime is 1661197591. The next prime is 1661197661. The reversal of 1661197617 is 7167911661.

It is a happy number.

1661197617 is a `hidden beast` number, since 16 + 6 + 1 + 19 + 7 + 617 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1622558961 + 38638656 = 40281^2 + 6216^2 .

It is not a de Polignac number, because 1661197617 - 2³⁰ = 587455793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661197667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 92288748 + ... + 92288765.

It is an arithmetic number, because the mean of its divisors is an integer number (399917947).

Almost surely, 2^1661197617 is an apocalyptic number.

It is an amenable number.

1661197617 is a deficient number, since it is larger than the sum of its proper divisors (738310065).

1661197617 is a wasteful number, since it uses less digits than its factorization.

1661197617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184577519 (or 184577516 counting only the distinct ones).

The product of its digits is 95256, while the sum is 45.

The square root of 1661197617 is about 40757.7921016338. The cubic root of 1661197617 is about 1184.3328253160.

The spelling of 1661197617 in words is "one billion, six hundred sixty-one million, one hundred ninety-seven thousand, six hundred seventeen".