891981477 has 20 divisors (see below), whose sum is σ = 1340660640. Its totient is φ = 590997384.

The previous prime is 891981473. The next prime is 891981479. The reversal of 891981477 is 774189198.

891981477 is a `hidden beast` number, since 8 + 91 + 9 + 81 + 477 = 666.

891981477 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 891981477 - 2² = 891981473 is a prime.

It is a super-2 number, since 2×891981477² = 1591261910622203058, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891981473) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 20577 + ... + 46982.

It is an arithmetic number, because the mean of its divisors is an integer number (67033032).

Almost surely, 2^891981477 is an apocalyptic number.

It is an amenable number.

891981477 is a deficient number, since it is larger than the sum of its proper divisors (448679163).

891981477 is a wasteful number, since it uses less digits than its factorization.

891981477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67734 (or 67725 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 891981477 is about 29866.0589465701. The cubic root of 891981477 is about 962.6134938299.

The spelling of 891981477 in words is "eight hundred ninety-one million, nine hundred eighty-one thousand, four hundred seventy-seven".