18212647538 has 4 divisors (see below), whose sum is σ = 27318971310. Its totient is φ = 9106323768.

The previous prime is 18212647517. The next prime is 18212647559. The reversal of 18212647538 is 83574621281.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (18212647517) and next prime (18212647559).

It can be written as a sum of positive squares in only one way, i.e., 17449617409 + 763030129 = 132097^2 + 27623^2 .

It is a super-2 number, since 2×18212647538² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18212647492 and 18212647501.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4553161883 + ... + 4553161886.

Almost surely, 2^18212647538 is an apocalyptic number.

18212647538 is a deficient number, since it is larger than the sum of its proper divisors (9106323772).

18212647538 is an equidigital number, since it uses as much as digits as its factorization.

18212647538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9106323771.

The product of its digits is 645120, while the sum is 47.

The spelling of 18212647538 in words is "eighteen billion, two hundred twelve million, six hundred forty-seven thousand, five hundred thirty-eight".