891413557609 has 3 divisors (see below), whose sum is σ = 891414501757. Its totient is φ = 891412613462.

The previous prime is 891413557561. The next prime is 891413557613. The reversal of 891413557609 is 906755314198.

The square root of 891413557609 is 944147.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 891413557609 - 2¹³ = 891413549417 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (891413557009) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 472074 + ... + 1416220.

Almost surely, 2^891413557609 is an apocalyptic number.

891413557609 is the 944147-th square number.

891413557609 is the 472074-th centered octagonal number.

It is an amenable number.

891413557609 is a deficient number, since it is larger than the sum of its proper divisors (944148).

891413557609 is an frugal number, since it uses more digits than its factorization.

891413557609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1888294 (or 944147 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 58.

The spelling of 891413557609 in words is "eight hundred ninety-one billion, four hundred thirteen million, five hundred fifty-seven thousand, six hundred nine".