1991514861 has 24 divisors (see below), whose sum is σ = 3480969024. Its totient is φ = 1071066240.

The previous prime is 1991514841. The next prime is 1991514881. The reversal of 1991514861 is 1684151991.

1991514861 is a `hidden beast` number, since 19 + 9 + 151 + 486 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (1991514841) and next prime (1991514881).

It is not a de Polignac number, because 1991514861 - 2⁶ = 1991514797 is a prime.

It is a super-2 number, since 2×1991514861² = 7932262883167698642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991514841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 928675 + ... + 930816.

It is an arithmetic number, because the mean of its divisors is an integer number (145040376).

Almost surely, 2^1991514861 is an apocalyptic number.

It is an amenable number.

1991514861 is a deficient number, since it is larger than the sum of its proper divisors (1489454163).

1991514861 is a wasteful number, since it uses less digits than its factorization.

1991514861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859521 (or 1859518 counting only the distinct ones).

The product of its digits is 77760, while the sum is 45.

The square root of 1991514861 is about 44626.3919782902. The cubic root of 1991514861 is about 1258.1367566419.

The spelling of 1991514861 in words is "one billion, nine hundred ninety-one million, five hundred fourteen thousand, eight hundred sixty-one".