6561611431 has 4 divisors (see below), whose sum is σ = 6947588592. Its totient is φ = 6175634272.

The previous prime is 6561611429. The next prime is 6561611437. The reversal of 6561611431 is 1341161656.

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 6561611431 - 2¹ = 6561611429 is a prime.

It is a super-2 number, since 2×6561611431² = 86109489142859735522, 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 (6561611437) 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, 192988555 + ... + 192988588.

It is an arithmetic number, because the mean of its divisors is an integer number (1736897148).

Almost surely, 2^6561611431 is an apocalyptic number.

6561611431 is a deficient number, since it is larger than the sum of its proper divisors (385977161).

6561611431 is a wasteful number, since it uses less digits than its factorization.

6561611431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385977160.

The product of its digits is 12960, while the sum is 34.

The square root of 6561611431 is about 81003.7741775036. The cubic root of 6561611431 is about 1872.1335929290.

The spelling of 6561611431 in words is "six billion, five hundred sixty-one million, six hundred eleven thousand, four hundred thirty-one".