6921804245 has 18 divisors (see below), whose sum is σ = 8609171298. Its totient is φ = 5342329888.

The previous prime is 6921804233. The next prime is 6921804277. The reversal of 6921804245 is 5424081296.

It can be written as a sum of positive squares in 3 ways, for example, as 796707076 + 6125097169 = 28226^2 + 78263^2 .

It is not a de Polignac number, because 6921804245 - 2¹⁶ = 6921738709 is a prime.

It is a super-2 number, since 2×6921804245² = 95822748012200040050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

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 17 ways as a sum of consecutive naturals, for example, 5394374 + ... + 5395656.

Almost surely, 2^6921804245 is an apocalyptic number.

It is an amenable number.

6921804245 is a deficient number, since it is larger than the sum of its proper divisors (1687367053).

6921804245 is an frugal number, since it uses more digits than its factorization.

6921804245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2629 (or 1317 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 41.

The square root of 6921804245 is about 83197.3812388347. The cubic root of 6921804245 is about 1905.7814889885.

The spelling of 6921804245 in words is "six billion, nine hundred twenty-one million, eight hundred four thousand, two hundred forty-five".