491457621636 has 36 divisors (see below), whose sum is σ = 1250522792064. Its totient is φ = 162734310000.

The previous prime is 491457621601. The next prime is 491457621653. The reversal of 491457621636 is 636126754194.

It is a happy number.

491457621636 is a `hidden beast` number, since 4 + 9 + 1 + 4 + 5 + 7 + 621 + 6 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×491457621636² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45198540 + ... + 45209411.

It is an arithmetic number, because the mean of its divisors is an integer number (34736744224).

Almost surely, 2^491457621636 is an apocalyptic number.

It is an amenable number.

491457621636 is an abundant number, since it is smaller than the sum of its proper divisors (759065170428).

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

491457621636 is a wasteful number, since it uses less digits than its factorization.

491457621636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90408112 (or 90408107 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The spelling of 491457621636 in words is "four hundred ninety-one billion, four hundred fifty-seven million, six hundred twenty-one thousand, six hundred thirty-six".