621656013161 has 4 divisors (see below), whose sum is σ = 621810619524. Its totient is φ = 621501406800.

The previous prime is 621656013059. The next prime is 621656013191. The reversal of 621656013161 is 161310656126.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 161310656126 = 2 ⋅80655328063.

It can be written as a sum of positive squares in 2 ways, for example, as 94529191936 + 527126821225 = 307456^2 + 726035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621656013161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621656013191) 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, 77297150 + ... + 77305191.

It is an arithmetic number, because the mean of its divisors is an integer number (155452654881).

Almost surely, 2^621656013161 is an apocalyptic number.

It is an amenable number.

621656013161 is a deficient number, since it is larger than the sum of its proper divisors (154606363).

621656013161 is a wasteful number, since it uses less digits than its factorization.

621656013161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154606362.

The product of its (nonzero) digits is 38880, while the sum is 38.

Adding to 621656013161 its reverse (161310656126), we get a palindrome (782966669287).

The spelling of 621656013161 in words is "six hundred twenty-one billion, six hundred fifty-six million, thirteen thousand, one hundred sixty-one".