705990687221 has 4 divisors (see below), whose sum is σ = 707522120844. Its totient is φ = 704459253600.

The previous prime is 705990687217. The next prime is 705990687239. The reversal of 705990687221 is 122786099507.

705990687221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122786099507 = 12409 ⋅9894923.

It can be written as a sum of positive squares in 2 ways, for example, as 339131522500 + 366859164721 = 582350^2 + 605689^2 .

It is a cyclic number.

It is not a de Polignac number, because 705990687221 - 2² = 705990687217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (705990687421) 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, 765716120 + ... + 765717041.

It is an arithmetic number, because the mean of its divisors is an integer number (176880530211).

Almost surely, 2^705990687221 is an apocalyptic number.

It is an amenable number.

705990687221 is a deficient number, since it is larger than the sum of its proper divisors (1531433623).

705990687221 is a wasteful number, since it uses less digits than its factorization.

705990687221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1531433622.

The product of its (nonzero) digits is 3810240, while the sum is 56.

The spelling of 705990687221 in words is "seven hundred five billion, nine hundred ninety million, six hundred eighty-seven thousand, two hundred twenty-one".