491806381 has 16 divisors (see below), whose sum is σ = 541427328. Its totient is φ = 443027200.

The previous prime is 491806373. The next prime is 491806417. The reversal of 491806381 is 183608194.

It is not a de Polignac number, because 491806381 - 2³ = 491806373 is a prime.

It is a super-2 number, since 2×491806381² = 483747032784634322, 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 (491806321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 796785 + ... + 797401.

It is an arithmetic number, because the mean of its divisors is an integer number (33839208).

Almost surely, 2^491806381 is an apocalyptic number.

It is an amenable number.

491806381 is a deficient number, since it is larger than the sum of its proper divisors (49620947).

491806381 is a wasteful number, since it uses less digits than its factorization.

491806381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 491806381 is about 22176.7080740131. The cubic root of 491806381 is about 789.3411057899.

The spelling of 491806381 in words is "four hundred ninety-one million, eight hundred six thousand, three hundred eighty-one".