6771521957 has 8 divisors (see below), whose sum is σ = 7172827992. Its totient is φ = 6370547200.

The previous prime is 6771521951. The next prime is 6771521971. The reversal of 6771521957 is 7591251776.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 42436 + 6771479521 = 206^2 + 82289^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6771521957 - 2¹⁸ = 6771259813 is a prime.

It is a super-2 number, since 2×6771521957² = 91707019228266219698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6771521951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40094 + ... + 123087.

It is an arithmetic number, because the mean of its divisors is an integer number (896603499).

Almost surely, 2^6771521957 is an apocalyptic number.

It is an amenable number.

6771521957 is a deficient number, since it is larger than the sum of its proper divisors (401306035).

6771521957 is a wasteful number, since it uses less digits than its factorization.

6771521957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165639.

The product of its digits is 926100, while the sum is 50.

The square root of 6771521957 is about 82289.2578469389. The cubic root of 6771521957 is about 1891.8880339835. Note that the first 3 decimals are identical.

The spelling of 6771521957 in words is "six billion, seven hundred seventy-one million, five hundred twenty-one thousand, nine hundred fifty-seven".