1091645678 has 4 divisors (see below), whose sum is σ = 1637468520. Its totient is φ = 545822838.

The previous prime is 1091645677. The next prime is 1091645689. The reversal of 1091645678 is 8765461901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8765461901 = 7 ⋅1252208843.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091645677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 272911418 + ... + 272911421.

It is an arithmetic number, because the mean of its divisors is an integer number (409367130).

Almost surely, 2^1091645678 is an apocalyptic number.

1091645678 is a deficient number, since it is larger than the sum of its proper divisors (545822842).

1091645678 is an equidigital number, since it uses as much as digits as its factorization.

1091645678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545822841.

The product of its (nonzero) digits is 362880, while the sum is 47.

The square root of 1091645678 is about 33040.0617130174. The cubic root of 1091645678 is about 1029.6601379725.

The spelling of 1091645678 in words is "one billion, ninety-one million, six hundred forty-five thousand, six hundred seventy-eight".