991656197 has 8 divisors (see below), whose sum is σ = 1134280896. Its totient is φ = 849271392.

The previous prime is 991656181. The next prime is 991656209. The reversal of 991656197 is 791656199.

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 991656197 - 2⁴ = 991656181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991656157) 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, 51023 + ... + 67724.

It is an arithmetic number, because the mean of its divisors is an integer number (141785112).

Almost surely, 2^991656197 is an apocalyptic number.

It is an amenable number.

991656197 is a deficient number, since it is larger than the sum of its proper divisors (142624699).

991656197 is a wasteful number, since it uses less digits than its factorization.

991656197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119947.

The product of its digits is 918540, while the sum is 53.

The square root of 991656197 is about 31490.5731449905. The cubic root of 991656197 is about 997.2109608256.

The spelling of 991656197 in words is "nine hundred ninety-one million, six hundred fifty-six thousand, one hundred ninety-seven".