1991654461 has 4 divisors (see below), whose sum is σ = 2096478400. Its totient is φ = 1886830524.

The previous prime is 1991654447. The next prime is 1991654477. The reversal of 1991654461 is 1644561991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1991654461 - 2¹⁵ = 1991621693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991652461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52411941 + ... + 52411978.

It is an arithmetic number, because the mean of its divisors is an integer number (524119600).

Almost surely, 2^1991654461 is an apocalyptic number.

It is an amenable number.

1991654461 is a deficient number, since it is larger than the sum of its proper divisors (104823939).

1991654461 is a wasteful number, since it uses less digits than its factorization.

1991654461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104823938.

The product of its digits is 233280, while the sum is 46.

The square root of 1991654461 is about 44627.9560477511. The cubic root of 1991654461 is about 1258.1661533239.

The spelling of 1991654461 in words is "one billion, nine hundred ninety-one million, six hundred fifty-four thousand, four hundred sixty-one".