891683981 has 4 divisors (see below), whose sum is σ = 902971200. Its totient is φ = 880396764.

The previous prime is 891683971. The next prime is 891683999. The reversal of 891683981 is 189386198.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 189386198 = 2 ⋅94693099.

It is a cyclic number.

It is not a de Polignac number, because 891683981 - 2¹⁸ = 891421837 is a prime.

It is a super-2 number, since 2×891683981² = 1590200643944016722, 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 (891683971) 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, 5643491 + ... + 5643648.

It is an arithmetic number, because the mean of its divisors is an integer number (225742800).

Almost surely, 2^891683981 is an apocalyptic number.

It is an amenable number.

891683981 is a deficient number, since it is larger than the sum of its proper divisors (11287219).

891683981 is a wasteful number, since it uses less digits than its factorization.

891683981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11287218.

The product of its digits is 746496, while the sum is 53.

The square root of 891683981 is about 29861.0780280954. The cubic root of 891683981 is about 962.5064641383.

The spelling of 891683981 in words is "eight hundred ninety-one million, six hundred eighty-three thousand, nine hundred eighty-one".