651997 has 2 divisors, whose sum is σ = 651998. Its totient is φ = 651996.

The previous prime is 651971. The next prime is 652019. The reversal of 651997 is 799156.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 556516 + 95481 = 746^2 + 309^2 .

It is a cyclic number.

It is not a de Polignac number, because 651997 - 2⁷ = 651869 is a prime.

It is a Chen prime.

It is an Ulam number.

651997 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325998 + 325999.

It is an arithmetic number, because the mean of its divisors is an integer number (325999).

2⁶⁵¹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

651997 is a deficient number, since it is larger than the sum of its proper divisors (1).

651997 is an equidigital number, since it uses as much as digits as its factorization.

651997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17010, while the sum is 37.

The square root of 651997 is about 807.4633118600. The cubic root of 651997 is about 86.7125316078.

It can be divided in two parts, 6 and 51997, that added together give a triangular number (52003 = T₃₂₂).

The spelling of 651997 in words is "six hundred fifty-one thousand, nine hundred ninety-seven".