1063951991 has 4 divisors (see below), whose sum is σ = 1064692800. Its totient is φ = 1063211184.

The previous prime is 1063951979. The next prime is 1063952003. The reversal of 1063951991 is 1991593601.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1991593601 = 1553 ⋅1282417.

It is an interprime number because it is at equal distance from previous prime (1063951979) and next prime (1063952003).

It is a cyclic number.

It is not a de Polignac number, because 1063951991 - 2²² = 1059757687 is a prime.

It is a super-2 number, since 2×1063951991² = 2263987678305728162, 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 (1063951901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 368246 + ... + 371123.

It is an arithmetic number, because the mean of its divisors is an integer number (266173200).

Almost surely, 2^1063951991 is an apocalyptic number.

1063951991 is a deficient number, since it is larger than the sum of its proper divisors (740809).

1063951991 is an equidigital number, since it uses as much as digits as its factorization.

1063951991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740808.

The product of its (nonzero) digits is 65610, while the sum is 44.

The square root of 1063951991 is about 32618.2769471350. The cubic root of 1063951991 is about 1020.8783895053.

The spelling of 1063951991 in words is "one billion, sixty-three million, nine hundred fifty-one thousand, nine hundred ninety-one".