1661600767 has 4 divisors (see below), whose sum is σ = 1672752600. Its totient is φ = 1650448936.

The previous prime is 1661600741. The next prime is 1661600779. The reversal of 1661600767 is 7670061661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7670061661 = 43 ⋅178373527.

It is a cyclic number.

It is not a de Polignac number, because 1661600767 - 2²³ = 1653212159 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661600867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5575693 + ... + 5575990.

It is an arithmetic number, because the mean of its divisors is an integer number (418188150).

Almost surely, 2^1661600767 is an apocalyptic number.

1661600767 is a deficient number, since it is larger than the sum of its proper divisors (11151833).

1661600767 is a wasteful number, since it uses less digits than its factorization.

1661600767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11151832.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 1661600767 is about 40762.7374816756. The cubic root of 1661600767 is about 1184.4286247068.

The spelling of 1661600767 in words is "one billion, six hundred sixty-one million, six hundred thousand, seven hundred sixty-seven".