6821491804951 has 4 divisors (see below), whose sum is σ = 6891816462832. Its totient is φ = 6751167147072.

The previous prime is 6821491804931. The next prime is 6821491805027. The reversal of 6821491804951 is 1594081941286.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6821491804951 - 2⁷ = 6821491804823 is a prime.

It is a super-2 number, since 2×6821491804951² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6821491804901) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 35162328795 + ... + 35162328988.

It is an arithmetic number, because the mean of its divisors is an integer number (1722954115708).

Almost surely, 2^{6821491804951} is an apocalyptic number.

6821491804951 is a deficient number, since it is larger than the sum of its proper divisors (70324657881).

6821491804951 is an equidigital number, since it uses as much as digits as its factorization.

6821491804951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70324657880.

The product of its (nonzero) digits is 4976640, while the sum is 58.

The spelling of 6821491804951 in words is "six trillion, eight hundred twenty-one billion, four hundred ninety-one million, eight hundred four thousand, nine hundred fifty-one".