661343983 has 2 divisors, whose sum is σ = 661343984. Its totient is φ = 661343982.

The previous prime is 661343941. The next prime is 661343989. The reversal of 661343983 is 389343166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661343983 - 2¹³ = 661335791 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661343989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330671991 + 330671992.

It is an arithmetic number, because the mean of its divisors is an integer number (330671992).

Almost surely, 2^661343983 is an apocalyptic number.

661343983 is a deficient number, since it is larger than the sum of its proper divisors (1).

661343983 is an equidigital number, since it uses as much as digits as its factorization.

661343983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 43.

The square root of 661343983 is about 25716.6090882916. The cubic root of 661343983 is about 871.2493535658.

The spelling of 661343983 in words is "six hundred sixty-one million, three hundred forty-three thousand, nine hundred eighty-three".