781368216653 has 4 divisors (see below), whose sum is σ = 781389198240. Its totient is φ = 781347235068.

The previous prime is 781368216619. The next prime is 781368216691. The reversal of 781368216653 is 356612863187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 356612863187 = 7 ⋅50944694741.

It is a cyclic number.

It is not a de Polignac number, because 781368216653 - 2²⁰ = 781367168077 is a prime.

It is a super-2 number, since 2×781368216653² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781368216053) 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, 10434833 + ... + 10509446.

It is an arithmetic number, because the mean of its divisors is an integer number (195347299560).

Almost surely, 2^781368216653 is an apocalyptic number.

It is an amenable number.

781368216653 is a deficient number, since it is larger than the sum of its proper divisors (20981587).

781368216653 is a wasteful number, since it uses less digits than its factorization.

781368216653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20981586.

The product of its digits is 8709120, while the sum is 56.

The spelling of 781368216653 in words is "seven hundred eighty-one billion, three hundred sixty-eight million, two hundred sixteen thousand, six hundred fifty-three".