51543691 has 2 divisors, whose sum is σ = 51543692. Its totient is φ = 51543690.

The previous prime is 51543689. The next prime is 51543733. The reversal of 51543691 is 19634515.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51543691 - 2¹ = 51543689 is a prime.

Together with 51543689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51543641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25771845 + 25771846.

It is an arithmetic number, because the mean of its divisors is an integer number (25771846).

Almost surely, 2^51543691 is an apocalyptic number.

51543691 is a deficient number, since it is larger than the sum of its proper divisors (1).

51543691 is an equidigital number, since it uses as much as digits as its factorization.

51543691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 34.

The square root of 51543691 is about 7179.3934980610. The cubic root of 51543691 is about 372.1561254517.

The spelling of 51543691 in words is "fifty-one million, five hundred forty-three thousand, six hundred ninety-one".