680921645 has 16 divisors (see below), whose sum is σ = 846462960. Its totient is φ = 525465600.

The previous prime is 680921623. The next prime is 680921651. The reversal of 680921645 is 546129086.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 73496329 + 607425316 = 8573^2 + 24646^2 .

It is not a de Polignac number, because 680921645 - 2¹⁸ = 680659501 is a prime.

It is a super-3 number, since 3×680921645³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 416 + ... + 36905.

It is an arithmetic number, because the mean of its divisors is an integer number (52903935).

Almost surely, 2^680921645 is an apocalyptic number.

It is an amenable number.

680921645 is a deficient number, since it is larger than the sum of its proper divisors (165541315).

680921645 is a wasteful number, since it uses less digits than its factorization.

680921645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37456.

The product of its (nonzero) digits is 103680, while the sum is 41.

The square root of 680921645 is about 26094.4753731513. The cubic root of 680921645 is about 879.7630409687.

The spelling of 680921645 in words is "six hundred eighty million, nine hundred twenty-one thousand, six hundred forty-five".