491541297401856 has 312 divisors, whose sum is σ = 1429528762784640. Its totient is φ = 149329001742336.

The previous prime is 491541297401831. The next prime is 491541297401863. The reversal of 491541297401856 is 658104792145194.

It is a tau number, because it is divible by the number of its divisors (312).

It is a super-2 number, since 2×491541297401856² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6222041739225 + ... + 6222041739303.

Almost surely, 2^{491541297401856} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 491541297401856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (714764381392320).

491541297401856 is an abundant number, since it is smaller than the sum of its proper divisors (937987465382784).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

491541297401856 is an frugal number, since it uses more digits than its factorization.

491541297401856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 87091200, while the sum is 66.

The spelling of 491541297401856 in words is "four hundred ninety-one trillion, five hundred forty-one billion, two hundred ninety-seven million, four hundred one thousand, eight hundred fifty-six".