18678101621 has 2 divisors, whose sum is σ = 18678101622. Its totient is φ = 18678101620.

The previous prime is 18678101581. The next prime is 18678101647. The reversal of 18678101621 is 12610187681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17237064100 + 1441037521 = 131290^2 + 37961^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18678101621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18678101681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9339050810 + 9339050811.

It is an arithmetic number, because the mean of its divisors is an integer number (9339050811).

Almost surely, 2^18678101621 is an apocalyptic number.

It is an amenable number.

18678101621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18678101621 is an equidigital number, since it uses as much as digits as its factorization.

18678101621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32256, while the sum is 41.

The spelling of 18678101621 in words is "eighteen billion, six hundred seventy-eight million, one hundred one thousand, six hundred twenty-one".