991413661 has 8 divisors (see below), whose sum is σ = 1160679744. Its totient is φ = 829056480.

The previous prime is 991413653. The next prime is 991413679. The reversal of 991413661 is 166314199.

It is a happy number.

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

It is not a de Polignac number, because 991413661 - 2³ = 991413653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991413611) 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, 1726915 + ... + 1727488.

It is an arithmetic number, because the mean of its divisors is an integer number (145084968).

Almost surely, 2^991413661 is an apocalyptic number.

It is an amenable number.

991413661 is a deficient number, since it is larger than the sum of its proper divisors (169266083).

991413661 is a wasteful number, since it uses less digits than its factorization.

991413661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3454451.

The product of its digits is 34992, while the sum is 40.

The square root of 991413661 is about 31486.7219792725. The cubic root of 991413661 is about 997.1296560082.

The spelling of 991413661 in words is "nine hundred ninety-one million, four hundred thirteen thousand, six hundred sixty-one".