661793394499 has 2 divisors, whose sum is σ = 661793394500. Its totient is φ = 661793394498.

The previous prime is 661793394497. The next prime is 661793394539. The reversal of 661793394499 is 994493397166.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661793394499 - 2¹ = 661793394497 is a prime.

It is a super-2 number, since 2×661793394499² (a number of 24 digits) contains 22 as substring.

Together with 661793394497, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (661793394497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330896697249 + 330896697250.

It is an arithmetic number, because the mean of its divisors is an integer number (330896697250).

Almost surely, 2^661793394499 is an apocalyptic number.

661793394499 is a deficient number, since it is larger than the sum of its proper divisors (1).

661793394499 is an equidigital number, since it uses as much as digits as its factorization.

661793394499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 238085568, while the sum is 70.

The spelling of 661793394499 in words is "six hundred sixty-one billion, seven hundred ninety-three million, three hundred ninety-four thousand, four hundred ninety-nine".