491542142921 has 4 divisors (see below), whose sum is σ = 496135994832. Its totient is φ = 486948291012.

The previous prime is 491542142909. The next prime is 491542142953. The reversal of 491542142921 is 129241245194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491542142921 is a prime.

It is a super-2 number, since 2×491542142921² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491542142521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2296925795 + ... + 2296926008.

It is an arithmetic number, because the mean of its divisors is an integer number (124033998708).

Almost surely, 2^491542142921 is an apocalyptic number.

It is an amenable number.

491542142921 is a deficient number, since it is larger than the sum of its proper divisors (4593851911).

491542142921 is a wasteful number, since it uses less digits than its factorization.

491542142921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4593851910.

The product of its digits is 207360, while the sum is 44.

The spelling of 491542142921 in words is "four hundred ninety-one billion, five hundred forty-two million, one hundred forty-two thousand, nine hundred twenty-one".