661379 has 4 divisors (see below), whose sum is σ = 665376. Its totient is φ = 657384.

The previous prime is 661373. The next prime is 661393. The reversal of 661379 is 973166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 973166 = 2 ⋅486583.

It is a cyclic number.

It is not a de Polignac number, because 661379 - 2¹⁶ = 595843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661373) 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, 1739 + ... + 2084.

It is an arithmetic number, because the mean of its divisors is an integer number (166344).

2⁶⁶¹³⁷⁹ is an apocalyptic number.

661379 is a deficient number, since it is larger than the sum of its proper divisors (3997).

661379 is a wasteful number, since it uses less digits than its factorization.

661379 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3996.

The product of its digits is 6804, while the sum is 32.

The square root of 661379 is about 813.2521134310. The cubic root of 661379 is about 87.1264730334.

The spelling of 661379 in words is "six hundred sixty-one thousand, three hundred seventy-nine".