651647 has 2 divisors, whose sum is σ = 651648. Its totient is φ = 651646.

The previous prime is 651641. The next prime is 651649. The reversal of 651647 is 746156.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 651647 - 2¹⁰ = 650623 is a prime.

Together with 651649, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325823 + 325824.

It is an arithmetic number, because the mean of its divisors is an integer number (325824).

2⁶⁵¹⁶⁴⁷ is an apocalyptic number.

651647 is a deficient number, since it is larger than the sum of its proper divisors (1).

651647 is an equidigital number, since it uses as much as digits as its factorization.

651647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 29.

The square root of 651647 is about 807.2465546535. The cubic root of 651647 is about 86.6970127131.

The spelling of 651647 in words is "six hundred fifty-one thousand, six hundred forty-seven".