1621128768713 has 4 divisors (see below), whose sum is σ = 1621149752448. Its totient is φ = 1621107784980.

The previous prime is 1621128768703. The next prime is 1621128768757. The reversal of 1621128768713 is 3178678211261.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1621128768713 - 2⁴ = 1621128768697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621128768703) 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, 10375553 + ... + 10530638.

It is an arithmetic number, because the mean of its divisors is an integer number (405287438112).

Almost surely, 2^{1621128768713} is an apocalyptic number.

It is an amenable number.

1621128768713 is a deficient number, since it is larger than the sum of its proper divisors (20983735).

1621128768713 is an equidigital number, since it uses as much as digits as its factorization.

1621128768713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20983734.

The product of its digits is 1354752, while the sum is 53.

The spelling of 1621128768713 in words is "one trillion, six hundred twenty-one billion, one hundred twenty-eight million, seven hundred sixty-eight thousand, seven hundred thirteen".