891388913 has 12 divisors (see below), whose sum is σ = 928745244. Its totient is φ = 855292800.

The previous prime is 891388909. The next prime is 891388957. The reversal of 891388913 is 319883198.

It can be written as a sum of positive squares in 6 ways, for example, as 739187344 + 152201569 = 27188^2 + 12337^2 .

It is not a de Polignac number, because 891388913 - 2² = 891388909 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (891388213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98195 + ... + 106887.

It is an arithmetic number, because the mean of its divisors is an integer number (77395437).

Almost surely, 2^891388913 is an apocalyptic number.

It is an amenable number.

891388913 is a deficient number, since it is larger than the sum of its proper divisors (37356331).

891388913 is an equidigital number, since it uses as much as digits as its factorization.

891388913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8836 (or 8795 counting only the distinct ones).

The product of its digits is 373248, while the sum is 50.

The square root of 891388913 is about 29856.1369403344. The cubic root of 891388913 is about 962.4002844469.

The spelling of 891388913 in words is "eight hundred ninety-one million, three hundred eighty-eight thousand, nine hundred thirteen".