191749661 has 8 divisors (see below), whose sum is σ = 196608384. Its totient is φ = 186899680.

The previous prime is 191749637. The next prime is 191749667. The reversal of 191749661 is 166947191.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 191749661 - 2¹⁰ = 191748637 is a prime.

It is a super-2 number, since 2×191749661² = 73535864987229842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191749667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83450 + ... + 85716.

It is an arithmetic number, because the mean of its divisors is an integer number (24576048).

Almost surely, 2^191749661 is an apocalyptic number.

It is an amenable number.

191749661 is a deficient number, since it is larger than the sum of its proper divisors (4858723).

191749661 is a wasteful number, since it uses less digits than its factorization.

191749661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4371.

The product of its digits is 81648, while the sum is 44.

The square root of 191749661 is about 13847.3701835403. The cubic root of 191749661 is about 576.6489889926.

The spelling of 191749661 in words is "one hundred ninety-one million, seven hundred forty-nine thousand, six hundred sixty-one".