661676768293 has 4 divisors (see below), whose sum is σ = 665332441228. Its totient is φ = 658021095360.

The previous prime is 661676768267. The next prime is 661676768309. The reversal of 661676768293 is 392867676166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 111755152804 + 549921615489 = 334298^2 + 741567^2 .

It is a cyclic number.

It is not a de Polignac number, because 661676768293 - 2¹⁷ = 661676637221 is a prime.

It is a super-2 number, since 2×661676768293² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661676768393) 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, 1827836196 + ... + 1827836557.

It is an arithmetic number, because the mean of its divisors is an integer number (166333110307).

Almost surely, 2^661676768293 is an apocalyptic number.

It is an amenable number.

661676768293 is a deficient number, since it is larger than the sum of its proper divisors (3655672935).

661676768293 is a wasteful number, since it uses less digits than its factorization.

661676768293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3655672934.

The product of its digits is 164602368, while the sum is 67.

The spelling of 661676768293 in words is "six hundred sixty-one billion, six hundred seventy-six million, seven hundred sixty-eight thousand, two hundred ninety-three".