1661155774 has 8 divisors (see below), whose sum is σ = 2559077928. Its totient is φ = 808129800.

The previous prime is 1661155751. The next prime is 1661155781. The reversal of 1661155774 is 4775511661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1661155774.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11223952 + ... + 11224099.

It is an arithmetic number, because the mean of its divisors is an integer number (319884741).

Almost surely, 2^1661155774 is an apocalyptic number.

1661155774 is a deficient number, since it is larger than the sum of its proper divisors (897922154).

1661155774 is a wasteful number, since it uses less digits than its factorization.

1661155774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22448090.

The product of its digits is 176400, while the sum is 43.

The square root of 1661155774 is about 40757.2787855127. The cubic root of 1661155774 is about 1184.3228813948.

The spelling of 1661155774 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, seven hundred seventy-four".