661404750293 has 4 divisors (see below), whose sum is σ = 755891143200. Its totient is φ = 566918357388.

The previous prime is 661404750263. The next prime is 661404750319. The reversal of 661404750293 is 392057404166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 661404750293 - 2⁶ = 661404750229 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661404750263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47243196443 + ... + 47243196456.

It is an arithmetic number, because the mean of its divisors is an integer number (188972785800).

Almost surely, 2^661404750293 is an apocalyptic number.

It is an amenable number.

661404750293 is a deficient number, since it is larger than the sum of its proper divisors (94486392907).

661404750293 is an equidigital number, since it uses as much as digits as its factorization.

661404750293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94486392906.

The product of its (nonzero) digits is 1088640, while the sum is 47.

The spelling of 661404750293 in words is "six hundred sixty-one billion, four hundred four million, seven hundred fifty thousand, two hundred ninety-three".