491778194987519 has 8 divisors (see below), whose sum is σ = 536525601634512. Its totient is φ = 447037504675840.

The previous prime is 491778194987507. The next prime is 491778194987557. The reversal of 491778194987519 is 915789491877194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 491778194987519 - 2³⁶ = 491709475510783 is a prime.

It is a super-2 number, since 2×491778194987519² (a number of 30 digits) 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 (491778194981519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1678930724 + ... + 1679223609.

It is an arithmetic number, because the mean of its divisors is an integer number (67065700204314).

Almost surely, 2^{491778194987519} is an apocalyptic number.

491778194987519 is a deficient number, since it is larger than the sum of its proper divisors (44747406646993).

491778194987519 is a wasteful number, since it uses less digits than its factorization.

491778194987519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3358167657.

The product of its digits is 11522165760, while the sum is 89.

The spelling of 491778194987519 in words is "four hundred ninety-one trillion, seven hundred seventy-eight billion, one hundred ninety-four million, nine hundred eighty-seven thousand, five hundred nineteen".