18621978469 has 2 divisors, whose sum is σ = 18621978470. Its totient is φ = 18621978468.

The previous prime is 18621978467. The next prime is 18621978491. The reversal of 18621978469 is 96487912681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18046698244 + 575280225 = 134338^2 + 23985^2 .

It is a cyclic number.

It is not a de Polignac number, because 18621978469 - 2¹ = 18621978467 is a prime.

It is a super-3 number, since 3×18621978469³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 18621978467, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18621978461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310989234 + 9310989235.

It is an arithmetic number, because the mean of its divisors is an integer number (9310989235).

Almost surely, 2^18621978469 is an apocalyptic number.

It is an amenable number.

18621978469 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621978469 is an equidigital number, since it uses as much as digits as its factorization.

18621978469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10450944, while the sum is 61.

The spelling of 18621978469 in words is "eighteen billion, six hundred twenty-one million, nine hundred seventy-eight thousand, four hundred sixty-nine".