680815787 has 4 divisors (see below), whose sum is σ = 683033736. Its totient is φ = 678597840.

The previous prime is 680815781. The next prime is 680815829. The reversal of 680815787 is 787518086.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 787518086 = 2 ⋅393759043.

It is a cyclic number.

It is not a de Polignac number, because 680815787 - 2²⁰ = 679767211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680815781) 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, 1108514 + ... + 1109127.

It is an arithmetic number, because the mean of its divisors is an integer number (170758434).

Almost surely, 2^680815787 is an apocalyptic number.

680815787 is a deficient number, since it is larger than the sum of its proper divisors (2217949).

680815787 is a wasteful number, since it uses less digits than its factorization.

680815787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2217948.

The product of its (nonzero) digits is 752640, while the sum is 50.

The square root of 680815787 is about 26092.4469339309. The cubic root of 680815787 is about 879.7174484578.

The spelling of 680815787 in words is "six hundred eighty million, eight hundred fifteen thousand, seven hundred eighty-seven".