491403120021 has 12 divisors (see below), whose sum is σ = 774332189280. Its totient is φ = 297820072680.

The previous prime is 491403119981. The next prime is 491403120067. The reversal of 491403120021 is 120021304194.

It is a happy number.

It is not a de Polignac number, because 491403120021 - 2¹⁴ = 491403103637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491403120421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2481833841 + ... + 2481834038.

It is an arithmetic number, because the mean of its divisors is an integer number (64527682440).

Almost surely, 2^491403120021 is an apocalyptic number.

It is an amenable number.

491403120021 is a deficient number, since it is larger than the sum of its proper divisors (282929069259).

491403120021 is a wasteful number, since it uses less digits than its factorization.

491403120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4963667896 (or 4963667893 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The spelling of 491403120021 in words is "four hundred ninety-one billion, four hundred three million, one hundred twenty thousand, twenty-one".