661584797 has 2 divisors, whose sum is σ = 661584798. Its totient is φ = 661584796.

The previous prime is 661584761. The next prime is 661584809. The reversal of 661584797 is 797485166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 399760036 + 261824761 = 19994^2 + 16181^2 .

It is a cyclic number.

It is not a de Polignac number, because 661584797 - 2¹² = 661580701 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661584757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330792398 + 330792399.

It is an arithmetic number, because the mean of its divisors is an integer number (330792399).

Almost surely, 2^661584797 is an apocalyptic number.

It is an amenable number.

661584797 is a deficient number, since it is larger than the sum of its proper divisors (1).

661584797 is an equidigital number, since it uses as much as digits as its factorization.

661584797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 53.

The square root of 661584797 is about 25721.2907335538. The cubic root of 661584797 is about 871.3550895552.

The spelling of 661584797 in words is "six hundred sixty-one million, five hundred eighty-four thousand, seven hundred ninety-seven".