668261519 has 4 divisors (see below), whose sum is σ = 669574920. Its totient is φ = 666948120.

The previous prime is 668261509. The next prime is 668261537. The reversal of 668261519 is 915162866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 915162866 = 2 ⋅457581433.

It is a cyclic number.

It is not a de Polignac number, because 668261519 - 2²⁰ = 667212943 is a prime.

It is a super-2 number, since 2×668261519² = 893146915552374722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 668261519.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668261509) 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, 655937 + ... + 656954.

It is an arithmetic number, because the mean of its divisors is an integer number (167393730).

Almost surely, 2^668261519 is an apocalyptic number.

668261519 is a deficient number, since it is larger than the sum of its proper divisors (1313401).

668261519 is a wasteful number, since it uses less digits than its factorization.

668261519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313400.

The product of its digits is 155520, while the sum is 44.

The square root of 668261519 is about 25850.7547085187. The cubic root of 668261519 is about 874.2765258949.

The spelling of 668261519 in words is "six hundred sixty-eight million, two hundred sixty-one thousand, five hundred nineteen".