18618621261 has 4 divisors (see below), whose sum is σ = 24824828352. Its totient is φ = 12412414172.

The previous prime is 18618621193. The next prime is 18618621283. The reversal of 18618621261 is 16212681681.

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 18618621261 - 2¹⁴ = 18618604877 is a prime.

It is a super-2 number, since 2×18618621261² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18618622261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3103103541 + ... + 3103103546.

It is an arithmetic number, because the mean of its divisors is an integer number (6206207088).

Almost surely, 2^18618621261 is an apocalyptic number.

It is an amenable number.

18618621261 is a deficient number, since it is larger than the sum of its proper divisors (6206207091).

18618621261 is an equidigital number, since it uses as much as digits as its factorization.

18618621261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6206207090.

The product of its digits is 55296, while the sum is 42.

The spelling of 18618621261 in words is "eighteen billion, six hundred eighteen million, six hundred twenty-one thousand, two hundred sixty-one".