661826879 has 12 divisors (see below), whose sum is σ = 788660208. Its totient is φ = 553442400.

The previous prime is 661826857. The next prime is 661826923. The reversal of 661826879 is 978628166.

It is not a de Polignac number, because 661826879 - 2⁸ = 661826623 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661826879.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661826839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162707 + ... + 166724.

It is an arithmetic number, because the mean of its divisors is an integer number (65721684).

Almost surely, 2^661826879 is an apocalyptic number.

661826879 is a deficient number, since it is larger than the sum of its proper divisors (126833329).

661826879 is a wasteful number, since it uses less digits than its factorization.

661826879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329486 (or 329479 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 53.

The square root of 661826879 is about 25725.9961711884. The cubic root of 661826879 is about 871.4613564367.

The spelling of 661826879 in words is "six hundred sixty-one million, eight hundred twenty-six thousand, eight hundred seventy-nine".